Method for producing mold for minute pattern transfer, method for producing diffraction grating using the same, and method for producing organic el element including the diffraction grating

ABSTRACT

A method for producing a mold includes: applying a block copolymer solution made of first and second polymers on a base member; performing a first annealing process at a temperature higher than Tg of the block copolymer after drying the coating film; forming a concavity and convexity structure on the base member by removing the second polymer by an etching process; performing a second annealing process of the concavity and convexity structure at a temperature higher than Tg of the first polymer; forming a seed layer on the structure; laminating or stacking a metal layer on the seed layer by an electroforming; and peeling off the metal layer from the base member. The second annealing process enables satisfactory transfer of a concavity and convexity structure on the base member onto the metal layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/938,597 filed on Jul. 10, 2013, which in turn is acontinuation application of International Patent Application No.PCT/JP2012/050564 filed on Jan. 13, 2012 claiming the benefit ofpriority of Japanese Patent Application No. 2011-6487 filed on Jan. 14,2011. The disclosure of the prior applications is hereby incorporated byreference herein in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for producing a mold forminute or fine pattern transfer used for nanoimprint and the like, amethod for producing a diffraction grating using the same, and a methodfor producing an organic EL element an organic EL element (OrganicElectro-Luminescence element or organic light emitting diode) includingthe diffraction grating as well as the mold for the minute patterntransfer, the diffraction grating, and the organic EL element, those ofwhich are obtained by using the methods described above.

2. Description of the Related Art

There has been known a lithography method as a method for forming aminute pattern such as a semiconductor integrated circuit. Theresolution of the pattern formed by the lithography method is dependenton the wavelength of a light source and/or the numerical aperture of anoptical system, and a light source having shorter wavelength is expectedin order to meet demand for miniaturized devices in recent years.However, the light source having the short wavelength is expensive,development thereof is not easy, and development of an optical materialtransmitting such a short-wavelength light is also needed. Further,manufacture of a large-area pattern by a conventional lithography methodrequires a large-size optical element, thereby having difficulties intechnical and economic aspects. Thus, a novel method for forming adesired pattern having a large area has been considered.

There has been known a nanoimprint method as the method for forming theminute pattern without using a conventional lithography apparatus. Thenanoimprint method is a technique such that a pattern of an order ofnanometer can be transferred by sandwiching resin between a mold and asubstrate. The nanoimprint method basically includes four steps of: i)application of a resin layer; ii) press of the mold; iii) patterntransfer; and iv) mold-releasing. The nanoimprint method is excellent inthat processing on a nanoscale can be realized by the simple process asdescribed above. Further, an apparatus used in the nanoimprint method issimple or easy, is capable of performing a large-area processing, andpromises a high throughput. Thus, the nanoimprint method is expected tocome into practical use in many fields such as a storage medium, anoptical member, and a biochip, in addition to a semiconductor device.

However, even in the nanoimprint method, a mold for transferring apattern having a line width of tens of nanometers basically requiresthat the pattern of a resist (resist pattern) on a silicon substrate isexposed and then is developed with using the lithography apparatus. Acurrent seed layer made of metal is formed on the resist pattern toperform electroforming of the mold with using the obtained resistpattern. However, in a case that definition of the pattern is not morethan 100 nm, coatability or coverage of the current seed layer formed onthe resist pattern by a sputtering is decreased, and the film thicknessof the current seed layer obtained varies among the upper portion, thesidewall, and the bottom portion (substrate exposed portion in a concaveportion of the pattern, that is a trench) of the resist pattern.Especially, a problem arises such that formation of the current seedlayer preferentially proceeds at the upper portion of the resist patternto cause a narrowing of a trench opening. Thus, in a case that a hole ortrench and a ridge are formed on the substrate by using a resist layer,there is a problem such that metal is less likely to be deposited on thebottom portion of the hole or trench during the formation of the currentseed layer; and overhang is caused at the upper portion of the ridge ofthe resist layer. In a case that the electroforming process of a stackedbody is performed by using such a current seed layer, an electroformedlayer is joined to the upper part of the hole or trench due to theoverhang and a void is left inside the trench. As a result, the moldobtained by the electroforming has a problem such that the mold has lowmechanical strength and therefore defects such as deformation of themold and pattern defect are caused.

In order to solve the problem(s) as described above, Japanese PatentApplication Laid-open No. 2010-017865 discloses a method formanufacturing a mold for nanoimprint including the steps of: forming aresist layer which includes a concavity and convexity pattern on asubstrate having a conductive surface and then exposing the conductivesurface at a concave portion of the concavity and convexity pattern ofthe resist layer; performing electroforming on the conductive surfaceexposed at the concave portion of the concavity and convexity pattern ofthe resist layer and then forming an electroformed layer having a filmthickness greater than that of the resist layer; and removing thesubstrate having the conductive surface and the resist layer. Accordingto this method, it is possible to grow the electroformed layer in onedirection, that is, in an upward direction from the conductive surfaceof the bottom portion of the resist pattern, without using the currentseed layer, and thus it is considered that no void exists inside themold for nanoimprint. However, even this method has still been forced todepend on the lithography method to make the mold used for thenanoimprint method.

The inventors of the present invention disclose, in InternationalApplication No. PCT/JP2010/62110, a method for obtaining a mold having aminute and irregular concavity and convexity pattern formed therein byapplying a block copolymer solution including a block copolymer and asolvent, satisfying a predetermined condition, onto a base member; andperforming drying to form a micro phase separation structure of theblock copolymer. According to this method, it is possible to obtain themold used for the nanoimprint and the like by using a self-organizingphenomenon of the block copolymer without using the lithography method.A mixture of a silicone-based polymer and a curing agent is dripped ontothe obtained mold and then cured to obtain the transferred pattern.Then, a glass substrate to which a curable resin has been applied ispressed against the transferred pattern and the curable resin is curedby irradiation with ultraviolet rays. In this way, a diffraction gratingin which a transferred pattern is duplicated is manufactured. It hasbeen confirmed that an organic EL element obtained by stacking atransparent electrode, an organic layer, and a metal electrode on thediffraction grating has sufficiently high light emission efficiency,sufficiently high level of external extraction efficiency, sufficientlylow wavelength-dependence of light emission, sufficiently lowdirectivity of light emission, and sufficiently high power efficiency.

It is desired to take the method for producing the diffraction gratingachieved in International Application No. PCT/JP2010/62110 by theinventor(s) of the present invention one step further, so as to improvethe method to be suitable for mass production of a product including theorganic EL element and the like.

In view of the above, an object of the present invention is to provide amethod for producing a mold for minute pattern transfer, which issuitable for production of an optical component such as a diffractiongrating used for general products including an organic EL element andthe like, a method for producing a diffraction grating using theobtained mold, and a method for producing an organic EL element usingsuch diffraction grating. Another object of the present invention is toprovide the mold for the minute pattern transfer, the diffractiongrating, and the organic EL element, using the producing methods asdescribed above.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a method forproducing a mold for minute or fine pattern transfer, including: a stepof applying a block copolymer solution made of at least a first polymer(segment) and a second polymer (segment) on a surface of a base member;a step of drying a coating film on the base member; a first heating stepfor heating the coating film after the drying at a temperature higherthan a glass transition temperature of a block copolymer of the blockcopolymer solution; an etching step for etching the coating film afterthe first heating step to remove the second polymer so that a concavityand convexity structure is formed on the base member; a second heatingstep for heating the concavity and convexity structure at a temperaturehigher than a glass transition temperature of the first polymer(segment); a step of forming a seed layer on the concavity and convexitystructure after the second heating step; a step of laminating orstacking a metal layer on the seed layer by an electroforming; and astep of peeling off the base member having the concavity and convexitystructure from the metal layer and the seed layer.

In the method for producing the mold according to the present invention,a micro phase separation structure of the block copolymer may begenerated during the drying step or the first heating step, and themicro phase separation structure preferably has a lamellar form.

In the method for producing the mold according to the present invention,the concavity and convexity structure may be heated, for 10 minutes to100 hours, at a temperature ranging from the glass transitiontemperature of the first polymer to a temperature higher than the glasstransition temperature of the first polymer by 70 degrees Celsius duringthe second heating step. Further, the concavity and convexity structurecan be deformed to have a chevron-shaped structure during the secondheating step.

In the method for producing the mold according to the present invention,a number average molecular weight (Mn) of the block copolymer ispreferably 500,000 or more and a molecular weight distribution (Mw/Mn)of the block copolymer is preferably 1.5 or less. Further, a volumeratio between the first polymer and the second polymer in the blockcopolymer is preferably 3:7 to 7:3 and a difference between solubilityparameters of the first and second polymers is preferably 0.1 to 10(cal/cm³)^(1/2) for forming the micro phase separation structure.

In the method for producing the mold according to the present invention,the first polymer forming the block copolymer is preferably polystyreneand the second polymer forming the block copolymer is preferablypolymethyl methacrylate. In the block copolymer solution, polyalkyleneoxide may be contained as a different homopolymer.

In the method for producing the mold according to the present invention,the seed layer may be formed by one of a non-electrolytic platingmethod, a sputtering method, and a vapor deposition method. Further, themethod for producing the mold according to the present invention mayinclude cleaning the mold obtained by peeling off the base member havingthe concavity and convexity structure from the metal layer and the seedlayer; and performing a mold-release treatment on a surface of the mold.

According to the second aspect of the present invention, there areprovided a method for producing a diffraction grating, including:pressing the mold obtained by the method for producing the mold to atransparent substrate to which a curable resin has been applied; curingthe curable resin; and detaching the mold from the transparent substrateto obtain a structure having a concavity and convexity structure on thetransparent substrate.

In the method for producing a diffraction grating according to thepresent invention, the structure may be the diffraction grating.

Further, the method for producing a diffraction grating according to thepresent invention may include: pressing the structure to a substrate towhich a sol-gel material has been applied; curing the sol-gel material;and detaching the structure from the substrate to obtain the diffractiongrating having a concavity and convexity structure made of the sol-gelmaterial.

According to the third aspect of the present invention, there isprovided a method for producing an organic EL element, wherein atransparent electrode, an organic layer, and a metal electrode isstacked in this order on the concavity and convexity structure of thediffraction grating produced by the method for producing the diffractiongrating, thereby producing the organic EL element.

According to the fourth aspect of the present invention, there isprovided the mold for minute pattern transfer produced by the producingmethod as defined in the first aspect.

According to the fifth aspect of the present invention, there isprovided the diffraction grating produced by the producing method asdefined in the second aspect. A cross-section shape of the concavity andconvexity structure of the surface of the diffraction grating preferablyhas a chevron shape. Further, in a case that a Fourier-transformed imageis obtained by performing a two-dimensional fast Fourier-transformprocessing on an concavity and convexity analysis image obtained by ananalyzing a planar shape of the concavity and convexity structure withan atomic force microscope, it is preferable that theFourier-transformed image shows an annular pattern substantiallycentered at an origin at which an absolute value of wavenumber is 0 μm⁻¹and that the annular or circular pattern is present within a regionwhere the absolute value of wavenumber is 10 μm⁻¹, especially within arange of from 1.25 to 5 μm⁻¹. A kurtosis of the cross-section shape ofthe concavity and convexity structure of the diffraction grating ispreferably −1.2 or more, especially preferably −1.2 to 1.2. An averagepitch of the cross-section of the concavity and convexity structure ofthe diffraction grating is preferably 10 to 600 nm.

According to the sixth aspect of the present invention, there isprovided an organic EL element produced by the producing method asdefined in the third aspect.

According to a method for producing a mold of the present invention, byperforming a second heating process to a block copolymer after anetching, a cross-section of a concavity and convexity structure of theblock copolymer has a smooth chevron shape. Accordingly, the concavityand convexity structure of the block copolymer can be completely coveredwith a seed layer having a uniform film thickness and it is possible tomanufacture an electroformed mold having high mechanical strengthwithout causing a pattern defect or the like. With respect to surfacetexture of a metal layer of the obtained mold, since concavities andconvexities are distributed substantially uniformly, residue of resin onthe side of the mold is suppressed when the block copolymer and a basemember are peeled off from the mold, and thus contamination of the moldis reduced and peeling property of the mold is improved. Accordingly, itis possible to obtain the mold having the high mechanical strengthwithout causing the pattern defect. Cleaning of the mold is alsoperformed easily. Even when the molecular weight of the block copolymeris increased, it is possible to reliably form the mold having a desiredconcavity and convexity pattern. By performing the second heating stepafter the etching, it is possible to remove impurities including, forexample, a solvent remained in the step before the second heating stepsuch as the etching. By using a method for producing a diffractiongrating according to the present invention, it is possible to produce,with relative ease, the diffraction grating which diffracts light in avisible region with low directivity and without wavelength-dependence.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1H are schematic illustration showing each step of a method forproducing a mold of the present invention.

FIGS. 2A-2E are schematic illustration showing each step for producing adiffraction grating using the mold obtained by the method for producingthe mold of the present invention.

FIG. 3 is a flowchart showing each step for the method for producing themold of the present invention.

FIG. 4 is a schematic illustration showing a stacked structure of anorganic EL element, in which the diffraction grating obtained by themethod for producing the diffraction grating of the present invention isused.

FIG. 5A is a transmission electron micrograph of a cross-section of acoating film after a first annealing process obtained in Example 1.

FIG. 5B is a scanning electron micrograph of a cross-section of a nickelmold from which a polymer component has been removed in Example 1.

FIG. 5C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by an etching process inExample 1 by use of a scanning probe microscope is displayed on adisplay.

FIG. 5D is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold, which hasbeen formed by electroforming in Example 1, by use of the scanning probemicroscope is displayed on a display.

FIG. 5E is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a diffractiongrating obtained in Example 1 by use of the scanning probe microscope isdisplayed on a display.

FIG. 5F is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex cross-section of thediffraction grating obtained in Example 1 by use of the scanning probemicroscope is displayed on a display.

FIG. 5G is a photograph showing a Fourier-transformed image, in which aresult of two-dimensional fast Fourier transform processing conducted ona concavity and convexity analysis image, which was obtained by use ofan atomic force microscope, of the surface of the diffraction gratingobtained in Example 1, is displayed on a display.

FIG. 6A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inExample 2 by use of the scanning probe microscope is displayed on adisplay.

FIG. 6B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymertreated to have a shape of chevrons by a second annealing process afterthe etching process in Example 2 by use of the scanning probe microscopeis displayed on a display.

FIG. 6C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Example 2 by use of the scanning probe microscopeis displayed on a display.

FIG. 6D is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a diffractiongrating obtained in Example 2 by use of the scanning probe microscope isdisplayed on a display.

FIG. 6E is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex cross-section of thediffraction grating obtained in Example 2 by use of the scanning probemicroscope is displayed on a display.

FIG. 6F is a photograph showing a Fourier-transformed image, in which aresult of two-dimensional fast Fourier transform processing conducted ona concavity and convexity analysis image, which was obtained by use ofthe atomic force microscope, of the surface of the diffraction gratingobtained in Example 2, is displayed on a display.

FIG. 6G is a graph showing a relation between a current efficiency and aluminance L′ of an organic EL element obtained in Example 2.

FIG. 6H is a graph showing a relation between a power efficiency and theluminance L′ of the organic EL element obtained in Example 2.

FIG. 7A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inExample 3 by use of the scanning probe microscope is displayed on adisplay.

FIG. 7B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymertreated to have the shape of chevrons by the second annealing processafter the etching process in Example 3 by use of the scanning probemicroscope is displayed on a display.

FIG. 7C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a diffractiongrating obtained in Example 3 by use of the scanning probe microscope isdisplayed on a display.

FIG. 7D is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex cross-section of thediffraction grating obtained in Example 3 by use of the scanning probemicroscope is displayed on a display.

FIG. 7E is a photograph showing a Fourier-transformed image, in which aresult of two-dimensional fast Fourier transform processing conducted ona concavity and convexity analysis image, which was obtained by use ofthe atomic force microscope, of the surface of the diffraction gratingobtained in Example 3, is displayed on a display.

FIG. 8A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inExample 4 by use of the scanning probe microscope is displayed on adisplay.

FIG. 8B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymertreated to have the shape of chevrons by the second annealing processafter the etching process in Example 4 by use of the scanning probemicroscope is displayed on a display.

FIG. 8C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a diffractiongrating obtained in Example 4 by use of the scanning probe microscope isdisplayed on a display.

FIG. 8D is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex cross-section of thediffraction grating obtained in Example 4 by use of the scanning probemicroscope is displayed on a display.

FIG. 8E is a photograph showing a Fourier-transformed image, in which aresult of two-dimensional fast Fourier transform processing conducted ona concavity and convexity analysis image, which was obtained by use ofthe atomic force microscope, of the surface of the diffraction gratingobtained in Example 4, is displayed on a display.

FIG. 8F is a graph showing a relation between a current efficiency and aluminance L′ of an organic EL element obtained in Example 4.

FIG. 8G is a graph showing a relation between a power efficiency and theluminance L′ of the organic EL element obtained in Example 4.

FIG. 9A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a diffractiongrating obtained in Example 5 by use of the scanning probe microscope isdisplayed on a display.

FIG. 9B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex cross-section of thediffraction grating obtained in Example 5 by use of the scanning probemicroscope is displayed on a display.

FIG. 9C is a photograph showing a Fourier-transformed image, in which aresult of two-dimensional fast Fourier transform processing conducted ona concavity and convexity analysis image, which was obtained by use ofthe atomic force microscope, of the surface of the diffraction gratingobtained in Example 5, is displayed on a display.

FIG. 10A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inExample 6 by use of the scanning probe microscope is displayed on adisplay.

FIG. 10B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Example 6 by use of the scanning probe microscopeis displayed on a display.

FIG. 10C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a diffractiongrating obtained in Example 6 by use of the scanning probe microscope isdisplayed on a display.

FIG. 10D is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex cross-section of thediffraction grating obtained in Example 6 by use of the scanning probemicroscope is displayed on a display.

FIG. 10E is a photograph showing a Fourier-transformed image, in which aresult of two-dimensional fast Fourier transform processing conducted ona concavity and convexity analysis image, which was obtained by use ofthe atomic force microscope, of the surface of the diffraction gratingobtained in Example 6, is displayed on a display.

FIG. 11A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inExample 7, by use of the scanning probe microscope is displayed on adisplay.

FIG. 11B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a diffractiongrating obtained in Example 7, by use of the scanning probe microscopeis displayed on a display.

FIG. 11C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex cross-section of thediffraction grating obtained in Example 7, by use of the scanning probemicroscope is displayed on a display.

FIG. 11D is a photograph showing a Fourier-transformed image, in which aresult of two-dimensional fast Fourier transform processing conducted ona concavity and convexity analysis image, which was obtained by use ofthe atomic force microscope, of the surface of the diffraction gratingobtained in Example 7, is displayed on a display.

FIG. 12A is a transmission electron micrograph of a cross-section of acoating film after the first annealing process obtained in Example 8.

FIG. 12B is a scanning electron micrograph, of a cross-section of anickel mold from which a polymer component has been removed in Example8.

FIG. 12C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inExample 8 by use of the scanning probe microscope is displayed on adisplay.

FIG. 12D is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Example 8 by use of the scanning probe microscopeis displayed on a display.

FIG. 12E is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of the diffractiongrating obtained in Example 8 by use of the scanning probe microscope isdisplayed on a display.

FIG. 12F is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex cross-section of thediffraction grating obtained in Example 8 by use of the scanning probemicroscope is displayed on a display.

FIG. 12G is a photograph showing a Fourier-transformed image, in which aresult of two-dimensional fast Fourier transform processing conducted ona concavity and convexity analysis image, which was obtained by use ofthe atomic force microscope, of the surface of the diffraction gratingobtained in Example 8, is displayed on a display.

FIG. 13A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inExample 9 by use of the scanning probe microscope is displayed on adisplay.

FIG. 13B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymertreated to have the shape of chevrons by the second annealing processafter the etching process in Example 9 by use of the scanning probemicroscope is displayed on a display.

FIG. 13C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Example 9 by use of the scanning probe microscopeis displayed on a display.

FIG. 13D is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a diffractiongrating obtained in Example 9 by use of the scanning probe microscope isdisplayed on a display.

FIG. 13E is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex cross-section of thediffraction grating obtained in Example 9 by use of the scanning probemicroscope is displayed on a display.

FIG. 13F is a photograph showing a Fourier-transformed image, in which aresult of two-dimensional fast Fourier transform processing conducted ona concavity and convexity analysis image, which was obtained by use ofthe atomic force microscope, of the surface of the diffraction gratingobtained in Example 9, is displayed on a display.

FIG. 14A is a scanning electron micrograph of a cross-section of anickel mold obtained in Comparative Example 1.

FIG. 14B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inComparative Example 1 by use of the scanning probe microscope isdisplayed on a display.

FIG. 14C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Comparative Example 1 by use of the scanning probemicroscope is displayed on a display.

FIG. 15A is a scanning electron micrograph of a cross-section of anickel mold obtained in Comparative Example 2.

FIG. 15B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inComparative Example 2 by use of the scanning probe microscope isdisplayed on a display.

FIG. 15C is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Comparative Example 2 by use of the scanning probemicroscope is displayed on a display.

FIG. 16A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inComparative Example 3 by use of the scanning probe microscope isdisplayed on a display.

FIG. 16B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Comparative Example 3 by use of the scanning probemicroscope is displayed on a display.

FIG. 17A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inComparative Example 4 by use of the scanning probe microscope isdisplayed on a display.

FIG. 17B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Comparative Example 4 by use of the scanning probemicroscope is displayed on a display.

FIG. 18 is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Comparative Example 5 by use of the scanning probemicroscope is displayed on a display.

FIG. 19 is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Comparative Example 6 by use of the scanning probemicroscope is displayed on a display.

FIG. 20 is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Comparative Example 7 by use of the scanning probemicroscope is displayed on a display.

FIG. 21A is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a block copolymerfrom which PMMA has been selectively removed by the etching process inComparative Example 8 by use of the scanning probe microscope isdisplayed on a display.

FIG. 21B is a photograph showing an analysis image, in which a result ofanalysis conducted on a concave and convex surface of a mold formed bythe electroforming in Comparative Example 8 by use of the scanning probemicroscope is displayed on a display.

FIG. 22 is a schematic illustration showing a stacked structure of anorganic EL element, in which a diffraction grating obtained by theproducing method of Example 10 is used.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, preferred embodiments of the present invention will bedescribed in detail with reference to the drawings.

At first, an explanation will be made about a method for producing amold suitable for producing a diffraction grating used for an organic ELelement and the like. As shown in the flowchart of FIG. 3, the methodfor producing the mold mainly includes a step (processing) of preparinga block copolymer solution, a step for applying the block copolymersolution, a drying step, a first heating step, an etching step, a secondheating step, a seed layer forming step, an electroforming step, and areleasing or peeling step. Hereinafter, an explanation will be madeabout each step and each subsequent step of the method for producing themold with reference to schematic illustrations of FIGS. 1 and 2 asappropriate.

<Preparation Step of Block Copolymer Solution>

The block copolymer used for the present invention includes at least afirst polymer segment made of a first homopolymer and a second polymersegment made of a second homopolymer different from the firsthomopolymer. The second homopolymer desirably has a solubility parameterwhich is higher than a solubility parameter of the first homopolymer by0.1 to 10 (cal/cm³)^(1/2). In a case that the difference between thesolubility parameters of the first and second homopolymers is less than0.1 (cal/cm³)^(1/2), it is difficult to form a regular micro phaseseparation structure of the block copolymer. In a case that thedifference exceeds 10 (cal/cm³)^(1/2), it is difficult to prepare auniform solution of the block copolymer.

Examples of monomers serving as raw materials of homopolymers usable asthe first homopolymer and second homopolymer include styrene,methylstyrene, propylstyrene, butylstyrene, hexylstyrene, octylstyrene,methoxystyrene, ethylene, propylene, butene, hexene, acrylonitrile,acrylamide, methyl methacrylate, ethyl methacrylate, propylmethacrylate, butyl methacrylate, hexyl methacrylate, octylmethacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butylacrylate, hexyl acrylate, octyl acrylate, methacrylic acid, acrylicacid, hydroxyethyl methacrylate, hydroxyethyl acrylate, ethylene oxide,propylene oxide, dimethylsiloxane, lactic acid, vinylpyridine,hydroxystyrene, styrenesulfonate, isoprene, butadiene, ε-caprolactone,isopropylacrylamide, vinyl chloride, ethylene terephthalate,tetrafluoroethylene, and vinyl alcohol. Of these monomers, styrene,methyl methacrylate, ethylene oxide, butadiene, isoprene, vinylpyridine,and lactic acid are preferably used from the viewpoints that theformation of phase separation easily occurs, and that the concavitiesand convexities are easily formed by an etching.

In addition, examples of a combination of the first homopolymer and thesecond homopolymer include combinations of two selected from the groupconsisting of a styrene-based polymer (more preferably polystyrene),polyalkyl methacrylate (more preferably polymethyl methacrylate),polyethylene oxide, polybutadiene, polyisoprene, polyvinylpyridine, andpolylactic acid. Of these combinations, a combination of thestyrene-based polymer and polyalkyl methacrylate, a combination of thestyrene-based polymer and polyethylene oxide, a combination of thestyrene-based polymer and polyisoprene, a combination of thestyrene-based polymer and polybutadiene are more preferable, and thecombination of the styrene-based polymer and polymethyl methacrylate,the combination of the styrene-based polymer and polyisoprene, thecombination of the styrene-based polymer and polybutadiene areparticularly preferable, from the viewpoint that the depths of theconcavities and convexities formed in the block copolymer can be furtherincreased by preferentially removing one of the homopolymers by theetching process. A combination of polystyrene (PS) and polymethylmethacrylate (PMMA) is further preferable.

The number average molecular weight (Mn) of the block copolymer ispreferably 500,000 or more, and is more preferably 1,000,000 or more,and particularly preferably 1,000,000 to 5,000,000. In a case that thenumber average molecular weight is less than 500,000, the average pitchof the concavities and convexities formed by the micro phase separationstructure of the block copolymer is so small that the average pitch ofthe concavities and convexities of the obtained diffraction gratingbecomes insufficient. Especially, in a case of the diffraction gratingused for the organic EL element, since the diffraction grating needs todiffract illumination light over a range of wavelength of a visibleregion, the average pitch is desirably 100 to 600 nm, and thus thenumber average molecular weight (Mn) of the block copolymer ispreferably 500,000 or more. Further, according to experiments conductedby the inventors of the present invention, it has been appreciated that,in a case that the number average molecular weight (Mn) of the blockcopolymer is 500,000 or more, a desired concavity and convexity patterncan not be obtained by an electroforming, unless the second heating stepis performed after the etching step, as it will be described later.

The molecular weight distribution (Mw/Mn) of the block copolymer ispreferably 1.5 or less, and is more preferably 1.0 to 1.35. In a casethat the molecular weight distribution exceeds 1.5, it is difficult toform the regular micro phase separation structure of the blockcopolymer.

Note that the number average molecular weight (Mn) and the weightaverage molecular weight (Mw) of the block copolymer are values measuredby gel permeation chromatography (GPC) and converted to molecularweights of standard polystyrene.

In the block copolymer, a volume ratio between the first polymer segmentand the second polymer segment (the first polymer segment: the secondpolymer segment) is desirably 3:7 to 7:3 in order to create a lamellarstructure by self-organization or assembly, and is more preferably 4:6to 6:4. In a case that the volume ratio is out of the above-describedrange, a concavity and convexity pattern owing to the lamellar structureis difficult to form.

The block copolymer solution used in the present invention is preparedby dissolving the block copolymer in a solvent. Examples of the solventinclude aliphatic hydrocarbons such as hexane, heptane, octane, decane,and cyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene,and mesitylene; ethers such as diethyl ether, tetrahydrofuran, anddioxane; ketones such as acetone, methyl ethyl ketone, isophorone, andcyclohexanone; ether alcohols such as butoxyethyl ether, hexyloxyethylalcohol, methoxy-2-propanol, and benzyloxyethanol; glycol ethers such asethylene glycol dimethyl ether, diethylene glycol dimethyl ether,triglyme, propylene glycol monomethyl ether, and propylene glycolmonomethyl ether acetate; esters such as ethyl acetate, ethyl lactate,and γ-butyrolactone; phenols such as phenol and chlorophenol; amidessuch as N,N-dimethylformamide, N,N-dimethylacetamide, andN-methylpyrrolidone; halogen-containing solvents such as chloroform,methylene chloride, tetrachloroethane, monochlorobenzene, anddichlorobenzene; hetero-element containing compounds such as carbondisulfide; and mixture solvents thereof. A percentage content of theblock copolymer in the block copolymer solution is preferably 0.1 to 15%by mass, and more preferably 0.3 to 5% by mass, relative to 100% by massof the block copolymer solution.

In addition, the block copolymer solution may further include adifferent homopolymer (a homopolymer other than the first homopolymerand the second homopolymer in the block copolymer contained in thesolution: for example, when the combination of the first homopolymer andthe second homopolymer in the block copolymer is the combination ofpolystyrene and polymethyl methacrylate, the different homopolymer maybe any kind of homopolymer other than polystyrene and polymethylmethacrylate), a surfactant, an ionic compound, an anti-foaming agent, aleveling agent, and the like.

By containing the different homopolymer, the micro phase separationstructure of the block copolymer can be improved. For example,polyalkylene oxide can be used to increase the depths of the concavitiesand convexities formed by the micro phase separation structure. As thepolyalkylene oxide, polyethylene oxide or polypropylene oxide is morepreferable, and polyethylene oxide is particularly preferable. Inaddition, as the polyethylene oxide, one represented by the followingformula is preferable:

HO—(CH₂—CH₂—O)_(n)—H

[in the formula, n represents an integer of 10 to 5000 (more preferablyan integer of 50 to 1000, and further preferably an integer of 50 to500)]. In a case that the value of n is less than the lower limit, themolecular weight is so low that the effect obtained by containing thedifferent homopolymer becomes insufficient, because the polyethyleneoxide is lost due to volatilization, vaporization, or the like during aheating process at a high-temperature. In a case that the value exceedsthe upper limit, the molecular weight is so high that the molecularmobility is low. Hence, the speed of the phase separation is lowered,and the formation of the micro phase separation structure is adverselyaffected.

In addition, the number average molecular weight (Mn) of the differenthomopolymer is preferably 460 to 220,000, and is more preferably 2,200to 46,000. In a case that the number average molecular weight is lessthan the lower limit, the molecular weight is so low that the effectobtained by containing the different homopolymer becomes insufficient,because the different homopolymer is lost due to volatilization,vaporization, or the like during the heating process at thehigh-temperature. In a case that the number average molecular weightexceeds the upper limit, the molecular weight is so high that themolecular mobility is low. Hence, the speed of the phase separation islowered, and the formation of the micro phase separation structure isadversely affected.

The molecular weight distribution (Mw/Mn) of the different homopolymeris preferably 1.5 or less, and more preferably 1.0 to 1.3. In a casethat the molecular weight distribution exceeds the upper limit,uniformity of the shape of the micro phase separation is less likely tobe maintained. Note that the number average molecular weight (Mn) andthe weight average molecular weight (Mw) are values measured by gelpermeation chromatography (GPC) and converted to molecular weights ofstandard polystyrene.

In addition, when the different homopolymer is used in the presentinvention, it is preferable that the combination of the firsthomopolymer and the second homopolymer in the block copolymer be thecombination of polystyrene and polymethyl methacrylate(polystyrene-polymethyl methacrylate), and that the differenthomopolymer be a polyalkylene oxide. By using a polystyrene-polymethylmethacrylate block copolymer and polyalkylene oxide in combination asdescribed above, the orientation in the vertical direction is furtherimproved, thereby making it possible to further increase the depths ofthe concavities and convexities on the surface, and to shorten theheating process time during the manufacture.

In a case that the different homopolymer is used, the content thereof ispreferably 100 parts by mass or less, and more preferably 5 parts bymass to 100 parts by mass, relative to 100 parts by mass of the blockcopolymer. In a case that the content of the different homopolymer isless than the lower limit, the effect obtained by containing thedifferent homopolymer becomes insufficient.

In a case that the surfactant is used, the content thereof is preferably10 parts by mass or less relative to 100 parts by mass of the blockcopolymer. Moreover, in a case that the ionic compound is used, thecontent thereof is preferably 10 parts by mass or less relative to 100parts by mass of the block copolymer.

In a case that the block copolymer solution contains the differenthomopolymer, the total percentage content of the block copolymer and thedifferent homopolymer is preferably 0.1 to 15% by mass, and morepreferably 0.3 to 5% by mass, in the block copolymer solution. In a casethat the total percentage content is less than the lower limit, it isdifficult to uniformly apply the solution to attain a film thicknesssufficient to obtain a necessary film thickness. In a case that thetotal percentage content exceeds the upper limit, it is relativelydifficult to prepare a solution in which the block copolymer and thedifferent homopolymer are uniformly dissolved in the solvent.

<Application Step of Block Copolymer Solution>

According to the method for producing the mold of the present invention,as shown in FIG. 1A, the block copolymer solution prepared as describedabove is applied on a base member 10 to form a thin film 30. The basemember 10 is not especially limited, and is exemplified, for example, bysubstrates of resins such as polyimide, polyphenylene sulfide (PPS),polyphenylene oxide, polyether ketone, polyethylene naphthalate,polyethylene terephthalate, polyarylate, triacetyl cellulose, andpolycycloolefin; inorganic substrates such as glass, octadecyldimethylchlorosilane (ODS) treated glass, octadecyl trichlorosilane (OTS)treated glass, organo silicate treated glass, and silicon substrates;and substrates of metals such as aluminum, iron, and copper. Inaddition, the base member 10 may be subjected to surface treatments suchas an orientation treatment. By performing treatment on the surface ofthe substrate such as the glass with ODS, organo silicate or the like,the micro phase separation structure such as the lamellar structure, acylinder structure, and a globular or spherical structure is more likelyto be arranged perpendicular to the surface in a heating step as will bedescribed later on. The reason thereof is that domain of each blockforming the block copolymer is more likely to beperpendicularly-oriented by decreasing the difference in interfaceenergy between each block copolymer component and the surface of thesubstrate.

The method for applying the block copolymer solution is not particularlylimited, and, for example, a spin coating method, a spray coatingmethod, a dip coating method, a dropping method, a gravure printingmethod, a screen printing method, a relief printing method, a diecoating method, a curtain coating method, or an ink jet method can beemployed as the method.

The thickness of the thin film 30 of the block copolymer is preferablywithin a range which allows the thickness of a dried coating film, aswill be described later, to be 10 to 3000 nm, and more preferably withina range which allows the thickness of the dried coating film to be 50 to500 nm.

<Drying Step>

After the block copolymer solution is applied on the base member 10 toform the thin film 30, the thin film 30 on the base member 10 is dried.The drying can be performed in the ambient atmosphere. The temperaturefor drying the thin film 30 is not particularly limited, provided thatthe solvent can be removed from the thin film 30. For example, thetemperature is preferably 30 degrees Celsius to 200 degrees Celsius, andmore preferably 40 degrees Celsius to 100 degrees Celsius. It is notedthat concavities and convexities are found, in some cases, on thesurface of the thin film 30 when the formation of the micro phaseseparation structure of the block copolymer is started during the dryingstep.

<First Heating Step>

After the drying step, the thin film 30 is heated at a temperature ofnot less than a glass transition temperature (Tg) of the block copolymer(first heating step or annealing process). The heating step promotes theself-organization or assembly of the block copolymer, and the microphase separation of the block copolymer into portions of a first polymersegment 32 and second polymer segment 34 occurs as shown in FIG. 1B. Ina case that the heating temperature is less than the glass transitiontemperature of the block copolymer, the molecular mobility of thepolymer is so low that the self-organization or assembly of the blockcopolymer does not make progress adequately and thus the micro phaseseparation structure can not be formed enough or the heating timerequired for sufficiently generating the micro phase separationstructure is long. In addition, the upper limit of the heatingtemperature is not particularly limited, unless the block copolymer ispyrolyzed at the temperature. The first heating step can be performed inthe ambient atmosphere using an oven or the like. The drying step andthe heating step can be performed continuously by gradually increasingthe heating temperature. Accordingly, the drying step is included in theheating step.

<Etching Step>

After the first heating step, the etching process of the thin film 30 isperformed. Since the molecular structure of the first polymer segment 32is different from the molecular structure of the second polymer segment34, etchability of the first polymer segment 32 is also different fromthat of the second polymer segment 34. Therefore, by performing theetching process depending on each type of the polymer segments, that is,depending on each type of homopolymer, it is possible to selectivelyremove one of the polymer segments (second polymer segment 34) formingthe block copolymer. A remarkable concavity and convexity structureappears on the coating film by removing each second polymer segment 34from the micro phase separation structure in the etching process, asshown in FIG. 1C schematically. As the etching process, an etchingmethod using, for example, a reactive ion etching method, an ozoneoxidation method, a hydrolysis method, a metal ion staining method, anultraviolet-ray etching method, or the like can be employed. Moreover,as the etching process, a method may be employed in which covalent bondsin the block copolymer are cleaved by treating the covalent bonds withat least one selected from the group consisting of acids, bases, andreducing agents, and then the coating film in which the micro phaseseparation structure is formed is cleaned with a solvent which dissolvesonly one of the polymer segments, or the like, thereby removing only theone of the polymer segments, while keeping the micro phase separationstructure. In the embodiment(s) which will be described later, theultraviolet-ray etching is used in view of operability and the like.

<Second Heating Step>

The second heating process or the annealing process is performed to aconcavity and convexity structure 36 of the thin film 30 obtained by theetching step. The heating temperature in the second heating process isdesirably not less than the glass transition temperature of the firstpolymer segment 32 remaining after the etching, that is, not less thanthe glass transition temperature of the first homopolymer. For example,the heating temperature in the second heating process is desirably notless than the glass transition temperature of the first homopolymer andnot more than a temperature higher than the glass transition temperatureof the first homopolymer by 70 degrees Celsius. In a case that theheating temperature is less than the glass transition temperature of thefirst homopolymer, it is not possible to obtain a desired concavity andconvexity structure (that is, a smooth chevron structure) after theelectroforming, or a long time is required to perform the heating. In acase that the heating temperature is much higher than the glasstransition temperature of the first homopolymer, the first polymersegment 32 is melted and/or the shape of the first polymer segment 32 iscollapsed severely. Thus, it is not preferable. In view of the above,the heating is desirably performed within a range from the glasstransition temperature to the temperature higher than the glasstransition temperature by about 70 degrees Celsius. Similar to the firstheating process, the second heating process can be performed in theambient atmosphere using the oven or the like.

According to experiments of the inventors of the present invention, ithas been found out that a desired transfer pattern can not be obtainedin case that the concavity and convexity structure 36 of the coatingfilm obtained by the etching step is used as a master (master block) totransfer the concavity and convexity structure to a metallic mold by theelectroforming which will be described later. Especially, this problembecomes conspicuous as the molecular weight of the block copolymer ishigher. As described above, the molecular weight of the block copolymeris deeply linked with the micro phase separation structure, and thus thepitch of the diffraction grating obtained therefrom. Therefore, in acase that the diffraction grating is used for a purpose such as theorganic EL element, a distribution of the pitch is required to be suchthat diffraction occurs in a wavelength region such as the visibleregion including a wavelength range which is wide and includesrelatively long wavelength. In order to realize this, even when a blockcopolymer having a relatively high molecular weight is used, it isnecessary to reliably obtain, by the electroforming, a concavity andconvexity structure having the desired pitch distribution. In thepresent invention, by performing the heating process for the concavityand convexity structure obtained by the etching, a metallic mold, inwhich the concavity and convexity structure is also reflected enough, issuccessfully obtained in the subsequent electroforming step.

The reason thereof is considered by the inventors as follows. As shownin FIG. 1C conceptually, the concavity and convexity structure 36 afterthe etching is considered to have a complicated cross-section structure,in which the side surfaces of grooves defined by the concavity andconvexity structure are coarse and the concavities and convexities(including the overhang) are generated in a direction perpendicular to athickness direction. The following three problems are arisen by thecomplicated cross-section structure.

i) In the complicated cross-section structure, a portion at which a seedlayer for the electroforming is not attached is generated, and therebymaking it difficult to uniformly accumulate the metal layer by theelectroforming. As a result, it is considered that the obtained mold haslow mechanical strength and that defects such as deformation of the moldand pattern defect are caused.ii) In the electroforming (electroplating), a thickness of platingvaries depending on shapes of respective parts of an object to besubjected to the plating. In particular, a plated metal is more likelyto be attracted to convex portions and projecting or prominent cornersof the object, and is less likely to be attracted to concave portionsand hollow portions of the object. Also for these reasons, it isdifficult to obtain an electroformed film having a uniform filmthickness on the complicated concave and convex cross-section structureafter the etching.iii) Even when the complicated cross-section structure as describedabove can be transferred to the mold by the electroforming, in a casethat the concavity and convexity shape is tried to be transferred bypressing the mold against a curable resin, the curable resin enters gapsin the complicated cross-section structure of the mold. Hence, the moldcan not be released from the cured resin, or the pattern defect occursby fracture of the portion of the mold having the low strength.Conventionally, the transfer has been repeated usingpolydimethylsiloxane (PDMS) to prevent the above problem.

In the present invention, the first polymer segment 32 constructing theside surfaces of the grooves is subjected to the annealing process byheating the concavity and convexity structure after the etching.Thereby, as shown in FIG. 1D conceptually, each cross-section shapedefined by the first polymer segment 32 is formed of a relatively smoothand sloped surface to have a shape of chevron narrowing upward from thebase member (referred to as “chevron-shaped structure” in thisinvention). The overhang does not appear in such chevron-shapedstructure, and the chevron-shaped structure is duplicated into theinverted pattern in a metal layer accumulated on the first polymersegment 32, thereby the metal layer can be released easily. It hasbecome clear that the three problems can be solved by such effects ofthe second heating step as described above. FIG. 5B is a micrograph,taken by a scanning electron microscope (SEM), showing the cross-sectionstructure of the mold, which is formed, by Ni-electroforming using theconcavity and convexity structure obtained by the heating process afterthe etching process of the block copolymer, in Example 1 which will bedescribed later. The concavities and convexities are smooth, each convexportion has the gentle chevron shape, and no overhang is observed. Onthe other hand, FIG. 14B is a SEM micrograph showing the cross-sectionstructure of the mold, which is formed by the Ni-electroforming (nickelelectroforming) using the concavity and convexity structure obtainedwithout the second heating process after the etching process of theblock copolymer, in Comparative Example 1 which will be described later.It has been appreciated that Ni portions corresponding to white portionsin FIG. 14B form grooves each having a complicated shape including anoverhang structure; and that the resins (black portions in FIG. 14B) arepenetrated or entered into the grooves.

The base member 10, which has a chevron-shaped structure 38 obtained inthe second heating step, is used as a master for transfer in subsequentsteps. The average pitch of the concavities and convexities representingthe chevron-shaped structure 38 is preferably within a range from 100 to600 nm, and more preferably 200 to 600 nm. In a case that the averagepitch of the concavities and convexities is less than the lower limit,the pitches are so small relative to wavelengths of the visible lightthat required diffraction of the visible light is less likely to occurby using the diffraction grating obtained by use of such a master. In acase that the average pitch exceeds the upper limit, the diffractionangle of the diffraction grating obtained by use of such a master is solow that functions as the diffraction grating can not be fulfilledsufficiently. Note that the average pitch of the concavities andconvexities refers to an average value of pitches of the concavities andconvexities obtained when pitches of the concavities and convexities onthe surface of the cured resin layer (distances between adjacent concaveportions or between adjacent convex portions) are measured. In addition,a value which can be calculated as follows is employed as such averagevalue of the pitches of the concavities and convexities. A concavity andconvexity analysis image is obtained by measuring the shape of theconcavities and convexities on the surface by use of a scanning probemicroscope (for example, one manufactured by SII Nano Technology Inc.,under the product name of “E-sweep”, or the like), then the distancesbetween randomly selected adjacent convex portions or the distancesbetween randomly selected adjacent concave portions are measured at 100points or more in the concavity and convexity analysis image, and thenan average of these distances is determined as the average value of thepitches of concavities and convexities.

In addition, the average height of the concavities and convexitiesrepresenting the chevron-shaped structure 38 is preferably within arange from 5 to 200 nm, more preferably within a range from 20 to 200nm, and further preferably within a range from 50 to 150 nm. In a casethat the average height of the concavities and convexities is less thanthe lower limit, the height is so small relative to the wavelengths ofthe visible light that the diffraction is insufficient. In a case thatthe average height exceeds the upper limit, the following tendency isfound. When the obtained diffraction grating is used as an opticalelement on the light extraction port side of the organic EL element, theelement tends to be easily destructed and the life thereof tends to beshortened because of heat generation which occurs when the electricfield distribution in the EL layer becomes non-uniform, and henceelectric fields concentrate on a certain position or area. Note that theaverage height of the concavities and convexities refers to an averagevalue of the heights of the concavities and convexities obtained whenheights of the concavities and convexities (the distances betweenconcave portions and convex portions in the depth direction) on thesurface of the cured resin layer are measured. In addition, a valuecalculated as follows is employed as the average value of the heights ofthe concavities and convexities. That is, a concavity and convexityanalysis image is obtained by measuring the shape of the concavities andconvexities on the surface by use of the scanning probe microscope (forexample, one manufactured by SII NanoTechnology Inc., under the productname of “E-sweep”, or the like), then the distances between randomlyselected concave portions and convex portions in the depth direction aremeasured at 100 points or more in the concavity and convexity analysisimage, and then the average of the distances is determined as theaverage value of heights of concavities and convexities.

<Seed Layer Forming Step and Electroforming Step>

As shown in FIG. 1E, a seed layer 40 functioning as an electroconductivelayer for a subsequent electroforming process is formed on the surfaceof the chevron-shaped structure 38 of the master obtained as describedabove. The seed layer 40 can be formed by non-electrolytic plating,sputtering, or vapor deposition. The thickness of the seed layer 40 ispreferably not less than 10 nm and more preferably not less than 100 nmto uniformalize current density during the subsequent electroformingprocess, and thereby making the thickness of the metal layer accumulatedby the subsequent electroforming process to be constant. As a materialof the seed layer, it is possible to use, for example, nickel, copper,gold, silver, platinum, titanium, cobalt, tin, zinc, chrome, gold-cobaltalloy, gold-nickel alloy, boron-nickel alloy, solder,copper-nickel-chromium alloy, tin-nickel alloy, nickel-palladium alloy,nickel-cobalt-phosphorus alloy, or alloy thereof. It is considered thatthe relatively smooth chevron-shaped structure as shown in FIG. 1D ismore likely to be attached to by the seed layer completely and with auniform thickness, compared with the complicated cross-section structureas shown in FIG. 1C.

Subsequently, the metal layer is accumulated on the seed layer 40 by theelectroforming (electroplating). The entire thickness of a metal layer50 including the thickness of the seed layer 40 can be, for example, 10to 3000 μm. As a material of the metal layer 50 accumulated by theelectroforming, it is possible to use any of metal species as describedabove which can be used as the seed layer 40. In view of wear resistanceas the mold and peeling property, nickel is preferable. In this case,nickel is also preferably used for the seed layer 40. The currentdensity during the electroforming may be, for example, 0.03 to 10 A/cm²for suppressing bridge to form a uniform metal layer and in view ofshortening of an electroforming time. Considering ease of the subsequentprocesses such as pressing to the resin layer, peeling, and cleaning,the formed metal layer 50 desirably has appropriate hardness andthickness. A diamond like carbon (DLC) process or a Cr platingprocessing treatment can be performed on the surface of the metal layerin order to improve the hardness of the metal layer formed by theelectroforming. Alternatively, the hardness of the surface may beimproved by further performing the heating process of the metal layer.

<Peeling Step>

The metal layer 50 including the seed layer obtained as described aboveis peeled off from the base member having the concavity and convexitystructure to obtain a mold as a father die. As a peeling method, themetal layer 50 may be peeled off physically, or the first homopolymerand the remained block copolymer may be dissolved to be removed by usingan organic solvent dissolving them, such as toluene, tetrahydrofuran(THF), and chloroform.

<Cleaning Step>

In a case that the mold is peeled off from the base member 10 having thechevron-shaped structure 38 as above-described, a part of the polymer60, like the first polymer segment, remains in the mold in some cases asshown in FIG. 1G. In such a case, each part 60 remained in the mold canbe removed by a cleaning. As a cleaning method, a wet cleaning or a drycleaning can be used. As the wet cleaning, the remained parts can beremoved by performing the cleaning with the organic solvent such astoluene and tetrahydrofuran, the surfactant, or an alkaline solution. Ina case that the organic solvent is used, an ultrasonic cleaning may becarried out. Alternatively, the remained parts may be removed byperforming an electrolytic cleaning. As the dry cleaning, the remainedparts can be removed by an ashing using ultraviolet rays and/or plasma.The wet cleaning and the dry cleaning may be used in combination. Afterthe cleaning as described above, a rinse process with pure water orpurified water may be performed, and then ozone irradiation may becarried out after a drying. Accordingly, a mold 70 having a desiredconcavity and convexity structure is obtained.

Next, an explanation will be made about a method for producing thediffraction grating used for the organic EL element and the like usingthe obtained mold 70 with reference to FIG. 2A to FIG. 2E.

<Mold-Release Treatment Step>

In a case that the concavity and convexity structure is transferred tothe resin using the mold 70, a mold-release treatment of the mold 70 maybe performed to improve the mold releasability from the resin. As themold-release treatment, a manner to decrease surface energy is commonlyused, and the mold-release treatment is not particularly limited andincludes, for example, a method in which a concave and convex surface 70a of the mold 70 is coated with a mold-release agent such as afluorine-based material and a silicon resin as shown in FIG. 2A, amethod in which the surface is subjected to a treatment using afluorine-based silane coupling agent, and a method in which a film of adiamond like carbon is formed on the surface.

<Step for Transferring Mold to Resin Layer>

By using the obtained mold 70, a mother die is produced by transferringthe concavity and convexity structure (pattern) of the mold to a layerformed of an organic material such as resin or an inorganic materialsuch as a sol-gel material. In the following description, an explanationwill be made by citing a resin layer 80 as a layer to which theconcavity and convexity pattern is transferred, as an example. In themethod of the transfer process, for example, the curable resin isapplied on a transparent supporting substrate 90, and then the resinlayer 80 is cured while pressing the concavity and convexity structureof the mold 70 against the resin layer 80, as shown in FIG. 2B. Thetransparent supporting substrate 90 is exemplified, for example, by basemembers made of a transparent inorganic substance such as glass; basemembers made of a resin such as polyethylene terephthalate (PET),polyethylene terenaphthalate (PEN), polycarbonate (PC), cycloolefinpolymer (COP), polymethyl methacrylate (PMMA), or polystyrene (PS);stacked base members having a gas barrier layer made of an inorganicsubstance such as SiN, SiO₂, SiC, SiO_(x)N_(y), TiO₂, or Al₂O₃ formed onthe surface of the base member made of any of the above-describedresins; and stacked base members having base members made of any of theabove-described resins and gas barrier layers made of any of theabove-described inorganic substances stacked alternately on each other.In addition, the thickness of the transparent supporting substrate maybe within a range from 1 to 500 μm.

Examples of the curable resin include epoxy resin, acrylic resin,urethane resin, melamine resin, urea resin, polyester resin, phenolresin, and cross-linking type liquid crystal resin. The thickness of thecured resin is preferably within a range from 0.5 to 500 μm. In a casethat the thickness is less than the lower limit, heights of theconcavities and convexities formed on the surface of the cured resinlayer are more likely to be insufficient. In a case that the thicknessexceeds the upper limit, an effect of volume change of the resin whichoccurs during upon curing is likely to be so large that the formation ofthe shape of the concavities and convexities tends to be insufficient.

As a method for applying the curable resin, it is possible to adoptvarious coating methods such as a spin coating method, a spray coatingmethod, a dip coating method, a dropping method, a gravure printingmethod, a screen printing method, a relief printing method, a diecoating method, a curtain coating method, an ink-jet method, and asputtering method. Moreover, the condition for curing the curable resinvaries depending on the kind of the resin used. For example, a curingtemperature is preferably within a range from room temperature to 250degrees Celsius, and a curing time is preferably within a range from 0.5minutes to 3 hours. Alternatively, a method may be employed in which thecurable resin is cured by irradiation with energy rays such asultraviolet rays or electron beams. In such a case, the amount of theirradiation is preferably within a range from 20 mJ/cm² to 5 J/cm².

Subsequently, the mold 70 is detached from the cured rein layer 80 in acured state. A method for detaching the mold 70 is not limited to amechanical peeling method, and can adopt any known method. Then, asshown in FIG. 2C, it is possible to obtain a resin film structure 100 inwhich the cured rein layer 80 having the concavities and convexities isformed on the transparent supporting substrate 90. The resin filmstructure 100 may be used, as it is, as the diffraction grating.Alternatively, as will be described later on, the resin film structure100 is further used as the mold to make a diffraction grating made ofthe organic material such as the resin or a structure made of theinorganic material such as the sol-gel material, and the structure madeof the organic material or the structure made of the inorganic materialcan be used as the diffraction grating.

The method for producing the mold of the present invention can be usednot only in production of the diffraction grating provided on the lightextraction port side of the organic EL element but also in production ofan optical component having a minute or fine pattern used for variousdevices. For example, the method for producing the mold of the presentinvention can be used to produce a wire grid polarizer, anantireflection film, or an optical element for providing a lightconfinement effect in a solar cell by being placed on the photoelectricconversion surface side of the solar cell.

As described above, the resin film structure 100 having a desiredpattern can be obtained. In a case that the inverted pattern of theresin film structure 100 is used as the diffraction grating, the resinfilm structure 100 obtained through the transfer process of the mold asdescribed above is used as the mother die; a curable resin layer 82 isapplied on another transparent supporting substrate 92 as shown in FIG.2D; and the curable resin layer 82 is cured while pressing the resinfilm structure 100 against the curable resin layer 82, similar to a casein which the resin film structure 100 is formed. Subsequently, the resinfilm structure 100 is peeled off from the curable resin layer 82 in acured state. Accordingly, a replica 110 as another resin film structureas shown in FIG. 2E can be obtained. Further, it is allowable to producea replica having the inverted pattern of the replica 110 by performingthe above transfer step using the replica 110 as a master and/or toproduce a sub-replica by repeating the above transfer step again usingthe replica having the inverted pattern as the master.

Next, an explanation will be made about a method for manufacturing astructure having concavities and convexities made of the sol-gelmaterial (hereinafter referred to as “sol-gel structure” as appropriate)by further using the obtained resin film structure 100 as the master. Amethod for forming a substrate having a concavity and convexity patternusing the sol-gel material mainly includes: a solution preparation stepfor preparing a sol solution; an application step for applying theprepared sol solution on the substrate; a drying step for drying thecoating film of the sol solution applied on the substrate; a pressingstep for pressing a mold with a transfer pattern; a pre-sintering stepduring which the coating film to which the mold is pressed is subjectedto the pre-sintering; a peeling step for peeling off the mold from thecoating film; and a main sintering step during which the coating film issubjected to the main sintering. Hereinbelow, an explanation will bemade about each of the steps sequentially.

<Sol-Gel Solution Preparation Step>

At first, a sol-gel solution is prepared to form a coating film to whicha pattern is transferred by a sol-gel method. For example, in a casethat silica is synthesized by the sol-gel method on the substrate, thesol solution of metal alkoxide (silica precursor) is prepared. Thesilica precursor is exemplified by metal alkoxides including, forexample, tetraalkoxide monomers such as tetramethoxysilane (TMOS),tetraethoxysilane (TEOS), tetra-i-propoxysilane, tetra-n-propoxysilane,tetra-i-butoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, andtetra-t-butoxysilane; trialkoxide monomers such as methyltrimethoxysilane, ethyl trimethoxysilane, propyl trimethoxysilane,isopropyl trimethoxysilane, phenyl trimethoxysilane, methyltriethoxysilane, ethyl triethoxysilane, propyl triethoxysilane,isopropyl triethoxysilane, phenyl triethoxysilane, methyltripropoxysilane, ethyl tripropoxysilane, propyl tripropoxysilane,isopropyl tripropoxysilane, phenyl tripropoxysilane, methyltriisopropoxysilane, ethyl triisopropoxysilane, propyltriisopropoxysilane, isopropyl triisopropoxysilane, phenyltriisopropoxysilane; a polymer obtained by polymerizing the abovemonomers in small amounts; and a composite material characterized inthat functional group and/or polymer is introduced into a part of thematerial. Further, the silica precursor is exemplified, for example, bymetal acetylacetonate, metal carboxylate, oxychloride, chloride, andmixtures thereof. The silica precursor, however, is not limited thereto.Examples of metal species include, in addition to Si, Ti, Sn, Al, Zn,Zr, In, and mixtures thereof, but are not limited thereto. It is alsopossible to use any appropriate mixture of precursors of the aboveoxidized metals.

In a case that a mixture of TEOS and MTES is used, the mixture ratiothereof can be 1:1, for example, in a molar ratio. The sol solutionproduces amorphous silica by performing hydrolysis and polycondensationreaction. An acid such as hydrochloric acid or an alkali such as ammoniais added in order to adjust pH of the solution as a synthesis condition.The pH is preferably not more than 4 or not less than 10. Water may beadded to perform the hydrolysis. An amount of water to be added can be1.5 times or more with respect to metal alkoxide species in the molarratio.

Examples of the solvent include alcohols such as methanol, ethanol,isopropyl alcohol (IPA), and butanol; aliphatic hydrocarbons such ashexane, heptane, octane, decane, and cyclohexane; aromatic hydrocarbonssuch as benzene, toluene, xylene, and mesitylene; ethers such as diethylether, tetrahydrofuran, and dioxane; ketones such as acetone, methylethyl ketone, isophorone, and cyclohexanone; ether alcohols such asbutoxyethyl ether, hexyloxyethyl alcohol, methoxy-2-propanol, andbenzyloxyethanol; glycols such as ethylene glycol and propylene glycol;glycol ethers such as ethylene glycol dimethyl ether, diethylene glycoldimethyl ether, and propylene glycol monomethyl ether acetate; esterssuch as ethyl acetate, ethyl lactate, and γ-butyrolactone; phenols suchas phenol and chlorophenol; amides such as N,N-dimethylformamide,N,N-dimethylacetamide, and N-methylpyrrolidone; halogen-containingsolvents such as chloroform, methylene chloride, tetrachloroethane,monochlorobenzene, and dichlorobenzene; hetero-element containingcompounds such as carbon disulfide; water; and mixture solvents thereof.Especially, ethanol and isopropyl alcohol are preferable. Further, amixture of water and ethanol and a mixture of water and isopropylalcohol are also preferable.

As an additive, it is possible to use, for example, polyethylene glycol,polyethylene oxide, hydroxypropylcellulose, and polyvinyl alcohol forviscosity adjustment; alkanolamine such as triethanolamine as a solutionstabilizer; β-diketone such as acetylacetone; β-ketoester; formamid;dimetylformamide; and dioxane.

The sol solution prepared as described above is applied on thesubstrate. As the substrate, substrates made of inorganic materials suchas glass, silica glass, and silicon substrates or substrates of resinssuch as polyethylene terephthalate (PET), polyethylene terenaphthalate(PEN), polycarbonate (PC), cycloolefin polymer (COP), polymethylmethacrylate (PMMA), polystyrene (PS), polyimide (PI), and polyarylatemay be used. The substrate may be transparent or opaque. In a case thata substrate having a concavity and convexity pattern obtained from thesubstrate is used for production of the organic EL element as will bedescribed later, the substrate desirably has resistance to heat andultraviolet (UV) light etc. In view of this, the substrates made of theinorganic materials such as the glass, the silica glass, and the siliconsubstrates are more preferable. It is allowable to perform a surfacetreatment or provide an easy-adhesion layer on the substrate in order toimprove adhesion property and to provide a gas barrier layer in order tokeep out moisture and/or gas such as oxygen. As a method for applyingthe sol solution, it is possible to use any application method such as abar coating method, a spin coating method, a spray coating method, a dipcoating method, a die coating method, and an ink-jet method. Among themethods as described above, the bar coating method, the die coatingmethod, and the spin coating method are preferable, because the solsolution can be uniformly applied on the substrate having a relativelylarge area and the application can be quickly completed prior togelation of the sol solution. It is noted that, since a desiredconcavity and convexity pattern by a sol-gel material layer is formed insubsequent steps, the surface of the substrate (including the surfacetreatment or the easy-adhesion layer in case that the surface treatmentor the easy-adhesion layer is present) may be flat, and the substrateitself does not have the desired concavity and convexity pattern.

After the application step, the substrate is kept in the atmosphere orunder reduced pressure to evaporate the solution in the applied coatingfilm (hereinafter referred to also as “sol-gel material layer” asappropriate). Subsequently, the resin film structure 100 (mold) ispressed against the coating film. In this situation, the resin filmstructure 100 may be pressed by using a pressing roll. A period of timeduring which the mold and the coating film are brought in contact witheach other in a roll process is shorter than that in a pressing system,and thus there are advantages such that it is possible to preventdeformation of pattern due to difference among coefficients of thermalexpansion of the mold, the substrate, a stage on which the substrate isprovided, and the like; it is possible to prevent generation of bubblesof gas in the pattern due to bumping of the solvent in the gel solutionor to prevent trace or mark of gas from being left; it is possible toreduce transfer pressure and peeling force due to line contact with thesubstrate (coating film), and thereby making it possible to deal with alarger substrate readily; no bubble is included during the pressing; andthe like. Further, the heating may be performed while pressing the resinfilm structure 100.

After the resin film structure 100 as the mold is pressed against thecoating film (sol-gel material layer), the coating film may be subjectedto the pre-sintering. The pre-sintering promotes gelation of the coatingfilm to solidify the pattern, and thereby the pattern is less likely tobe collapsed during the peeling. In a case that the pre-sintering isperformed, the heating is preferably performed at a temperature from 40degrees Celsius to 150 degrees Celsius in the atmosphere. It is notindispensable to perform the pre-sintering.

The resin film structure 100 is peeled off from the coating film(sol-gel material layer) after the pressing step or the pre-sinteringstep. In a case that the roll is used during the pressing, the peelingforce may be smaller than that in a case that a plate-shaped mold isused, and it is possible to easily peel off the mold from the coatingfilm without remaining the coating film in the mold.

After the resin film structure 100 is peeled off from the coating film(sol-gel material layer) on the substrate, the coating film is subjectedto the main sintering. Hydroxyl group and the like contained in silica(amorphous silica) forming the coating film is desorbed or eliminated bythe main sintering to further strengthen the coating film. The mainsintering may be performed at a temperature from 200 degrees Celsius to1200 degrees Celsius for about 5 minutes to 6 hours. Accordingly, thecoating film is cured, and thereby obtaining a sol-gel structure(diffraction grating) with a concavity and convexity pattern film whichcorresponds to the concavity and convexity pattern of the resin filmstructure 100, that is, a sol-gel structure (diffraction grating) inwhich the sol-gel material layer having the concavity and convexitypattern is directly formed on the flat substrate. In this situation,depending on a sintering temperature and a sintering time, the silica asthe sol-gel material layer is amorphous, crystalline, or in a mixturestate of the amorphous and the crystalline.

In a case that the replica 110 (or sol-gel structure) is duplicatedusing the resin film structure 100, or in a case that another replica isduplicated using the obtained replica 110 (or sol-gel structure), a filmmay be laminated or stacked, on the surface of the resin film structure100 or the replica 110 (or sol-gel structure) having the concavity andconvexity pattern, by a gas phase method such as an evaporation methodor a sputtering method. By stacking the film as described above, in acase that transfer etc. is performed with, for example, applying theresin onto the surface of the film, the adhesion between the substrateand the resin (for example, a UV curable resin) can be lowered, so thatthe master block is more likely to be easily peeled. Examples of thevapor-deposited film include metals such as aluminum, gold, silver,platinum, and nickel; and metal oxides such as aluminum oxide. Inaddition, the thickness of the vapor-deposited film is preferably 5 to500 nm. In a case that the thickness is less than the lower limit, auniform film is difficult to obtain, so that sufficient effect oflowering the adhesion is decreased. In a case that the thickness exceedsthe upper limit, the shape of the master block is more likely to bedull. In a case that the cured resin layer of the resin film structure100 or the replica 110 is made of a UV curable resin, postcure may beconducted as appropriate by, for example, ultraviolet light irradiation,after curing of the resin.

In the steps shown in FIGS. 2B and 2D, the curable resins 80, 82 areapplied on the transparent supporting substrates 90, 92, respectively.In addition, it is allowable to use one obtained as follows as themaster block. The curable resin is applied directly on the surface ofthe mold 70 which is the master block or the surface of the cured resinlayer 80, and then the cured resin is detached. Alternatively, insteadof applying the resin onto the surface of the master block, it isallowable to employ, as the master block, a concavity and convexity filmof the cured resin obtained as follows. That is, the master block ispressed onto the coating film of the resin, and the resin is cured.

<Method for Producing Organic EL Element>

Next, an explanation will be made about a method for producing anorganic EL element using the resin film obtained as described above orthe diffraction grating which is the sol-gel structure. Here, anexplanation will be made by taking a method for producing an organic ELelement using a diffraction grating made of a resin film 100 as anexample, with reference to FIG. 4.

At first, as shown in FIG. 4, a transparent electrode denoted by areference numeral 3 is stacked on a resin layer 80 of the resin film 100to maintain a concavity and convexity structure formed on the surface ofthe resin 80. As a material for the transparent electrode 3, forexample, indium oxide, zinc oxide, tin oxide, indium-tin oxide (ITO),which is a composite material thereof, gold, platinum, silver, or copperis used. Of these materials, ITO is preferable from the viewpoint of thetransparency and the electrical conductivity. The thickness of thetransparent electrode 3 is preferably within a range from 20 to 500 nm.In a case that the thickness is less than the lower limit, theelectrical conductivity is more likely to be insufficient. In a casethat the thickness exceeds the upper limit, there is possibility thatthe transparency is so insufficient that the emitted EL light cannot beextracted to the outside sufficiently. As a method for stacking thetransparent electrode 3, any known method such as a vapor depositionmethod or a sputtering method can be employed as appropriate. Of thesemethods, the vapor deposition method is preferably employed from theviewpoint of maintaining the shape of the concavities and convexitiesformed on the surface of the cured resin layer; and the sputteringmethod is preferably employed from the viewpoint of improving adhesionproperty. It is allowable to put a glass substrate on a side opposite tothe resin layer 80 of the resin film 100 before the transparentelectrode 3 is provided on the resin layer 80.

Next, an organic layer denoted by a reference numeral 4 as shown in FIG.4 is stacked on the transparent electrode 3 to maintain the shape of theconcavities and convexities formed on the surface of the resin 80. Theorganic layer 4 is not particularly limited, provided that the organiclayer 4 is one usable as an organic layer of the organic EL element. Asthe organic layer 4, any known organic layer can be used as appropriate.The organic layer 4 may be a stacked body of various organic thin films,and, for example, may be a stacked body of an anode buffer layer 11, ahole transporting layer 12, and an electron transporting layer 13 asshown in FIG. 4. Here, examples of materials for the anode buffer layer11 include copper phthalocyanine, PEDOT, and the like. Examples ofmaterials for the hole transporting layer 12 include derivatives oftriphenylamine, triphenyldiamine derivatives (TPD), benzidine,pyrazoline, styrylamine, hydrazone, triphenylmethane, carbazole, and thelike. Examples of materials for the electron transporting layer 13include aluminum-quinolinol complex (Alq), phenanthroline derivatives,oxadiazole derivatives, triazole derivatives, phenylquinoxalinederivatives, silole derivatives, and the like. The organic layer 4 maybe, for example, a stacked body of a hole injecting layer made of atriphenylamine derivative or the like, and a light emitting layer madeof a fluorescent organic solid such as anthracene, a stacked body of thelight emitting layer and an electron injecting layer made of a perylenederivative or the like, or a stacked body of these hole injecting layer,light emitting layer, and electron injecting layer.

The organic layer 4 may be a stacked body of the hole transportinglayer, the light emitting layer, and the electron transporting layer asexemplified in Example 22 as will be described later on. In this case,examples of materials of the hole transporting layer include aromaticdiamine compounds such as phthalocyanine derivatives, naphthalocyaninederivatives, porphyrin derivatives,N,N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine (TPD), and4,4′-bis[N-(naphthyl)-N-phenyl-amino]biphenyl(α-NPD); oxazole;oxadiazole; triazole; imidazole; imidazolone; stilbene derivatives;pyrazoline derivatives; tetrahydroimidazole; polyarylalkane; butadiene;and 4,4′,4″-tris(N-(3-methylphenyl)N-phenylamino)triphenylamine(m-MTDATA). The materials of the hole transporting layer, however, arenot limited thereto. By providing the light emitting layer, a holeinjected from the transparent electrode and electron injected from ametal electrode are recombined to occur light emission. Examples ofmaterials of the light emitting layer include metallo-organic complexsuch as anthracene, naphthalene, pyrene, tetracene, coronene, perylene,phthaloperylene, naphthaloperylene, diphenylbutadiene,tetraphenylbutadiene, coumarin, oxadiazole, bisbenzoxazoline, bisstyryl,cyclopentadiene, and aluminum-quinolinol complex (Alq3);tri-(p-terphenyl-4-yl)amine; 1-aryl-2,5-di(2-thienyl) pyrrolederivatives; pyran; quinacridone; rubren; distyrylbenzene derivatives;distyryl arylene derivatives; distyryl amine derivatives; and variousfluorescent pigments or dyes. Further, it is preferable thatlight-emitting materials selected from the above compounds are mixed asappropriate and then are used. Furthermore, it is possible to preferablyuse a material system generating emission of light from a spinmultiplet, such as a phosphorescence emitting material generatingemission of phosphorescence and a compound including, in a part of themolecules, a constituent portion formed by the above materials. Thephosphorescence emitting material preferably includes heavy metal suchas iridium. A host material having high carrier mobility may be dopedwith each of the light-emitting materials as a guest material togenerate the light emission using dipole-dipole interaction (Forstermechanism), electron exchange interaction (Dexer mechanism). Examples ofmaterials of the electron transporting layer include heterocyclictetracarboxylic anhydrides such as nitro-substituted fluorenederivatives, diphenylquinone derivatives, thiopyran dioxide derivatives,and naphthaleneperylene; and metallo-organic complex such ascarbodiimide, fluorenylidene methane derivatives, anthraquino dimethaneand anthrone derivarives, oxadiazole derivatives, andaluminum-quinolinol complex (Alq3). Further, in the oxadiazolederivatives mentioned above, it is also possible to use, as an electrontransporting material, thiadiazole derivatives in which oxygen atoms ofoxadiazole rings are substituted by sulfur atoms and quinoxalinederivatives having quinoxaline rings known as electron attractive group.Furthermore, it is also possible to use a polymeric material in whichthe above materials are introduced into a macromolecular chain or theabove materials are made to be a main chain of the macromolecular chain.It is noted that the hole transporting layer or the electrontransporting layer may also function as the light-emitting layer. Inthis case, there are two organic layers between the transparentelectrode and the metal electrode which will be described later.

From the viewpoint of facilitating charge injection or hole injectioninto any organic layer 4, a layer made of a metal fluoride such aslithium fluoride (LiF) or Li₂O₃, a highly active alkaline earth metalsuch as Ca, Ba, or Cs, an organic insulating material, or the like maybe provided on the transparent electrode 3 or the organic layer 4. Inaddition, from the viewpoint of facilitating the hole injection from thetransparent electrode, a layer made of triazole derivatives; oxadiazolederivatives; imidazole derivatives; polyarylalkane derivatives;pyrazoline derivatives and pyrazolone derivatives; phenylenediaminederivatives; arylamine derivatives; amino-substituted chalconederivatives; oxazole derivatives; styrylanthracene derivatives;fluorenon derivatives; hydrazone derivatives; stilbene derivatives;silazane derivatives; aniline copolymer; or a conductive polymeroligomer, in particular, thiophene oligomer, may be provided between theorganic layer and the transparent electrode as the hole injecting layer.

In a case that the organic layer 4 is a stacked body formed of the anodebuffer layer 11, the hole transporting layer 12, and the electrontransporting layer 13, the thicknesses of the anode buffer layer 11, thehole transporting layer 12, and the electron transporting layer 13 arepreferably within a range from 1 to 50 nm, a range from 5 to 200 nm, anda range from 5 to 200 nm, respectively, from the viewpoint ofmaintaining the shape of the concavities and convexities formed on thesurface of the cured resin layer. In a case that the organic layer 4 isa stacked body formed of the hole transporting layer, the light-emittinglayer, and the electron transporting layer, the thicknesses of the holetransporting layer, the light-emitting layer, and the electrontransporting layer are preferably within a range from 1 to 200 nm, arange from 5 to 100 nm, and a range from 5 to 200 nm, respectively. As amethod for stacking any organic layer 4, any known method such as avapor deposition method, a sputtering method, and a die coating methodcan be employed as appropriate. Of these methods, the vapor depositionmethod is preferably employed from the viewpoint of maintaining theshape of the concavities and convexities formed on the surface of theresin 80.

Subsequently, as shown in FIG. 4, a metal electrode denoted by areference numeral 5 is stacked on the organic layer 4 so as to maintainthe shape of the concavities and convexities formed on the surface ofthe resin 80 in the step for forming the organic EL element. Materialsof the metal electrode 5 are not particularly limited, and a substancehaving a small work function can be used as appropriate. Examples of thematerials include aluminum, MgAg, MgIn, and AlLi. The thickness of themetal electrode 5 is preferably within a range from 50 to 500 nm. In acase that the thickness is less than the lower limit, the electricalconductivity is more likely to be decreased. In a case that thethickness exceeds the upper limit, there is possibility that the shapeof the concavities and convexities is difficult to maintain. Any knownmethod such as a vapor deposition method and a sputtering method can beadopted to stack the metal electrode 5. Of these methods, the vapordeposition method is preferably employed from the viewpoint ofmaintaining the concavity and convexity structure formed on the surfaceof the resin 80. Accordingly, an organic EL element 200 having astructure as shown in FIG. 4 can be obtained.

In the method for producing the organic EL element of the presentinvention, the resin 80 on the base member 10 has the chevron-shapedstructure. Thus, each of the transparent electrode 3, the organic layer4, and the metal electrode 5 is readily stacked to maintain thechevron-shaped structure of the resin 80. Hence, it is possible tosufficiently suppress repetition of multiple reflection of lightgenerated in the organic layer 4 in the element due to total reflectionat each interface. Further, it is also possible to re-emit light whichhas been totally reflected at an interface between the transparentsupporting substrate and the air by diffraction effect. Furthermore,since each of the transparent electrode 3, the organic layer 4, and themetal electrode 5 is more likely to have the same structure as thechevron-shaped structure formed on the surface of the resin layer 80, aninter-electrode distance between the transparent electrode 3 and themetal electrode 5 is partially short. For this reason, in comparisonwith those in which the inter-electrode distance between the transparentelectrode 3 and the metal electrode 5 is uniform, an increase inelectric field intensity can be expected in application of voltage, andalso light emission efficiency of the organic EL element can beimproved.

In the diffraction grating produced according to the present inventionand the organic EL element including the diffraction grating, theaverage height of the concavities and convexities formed on the surface(the cured surface of curable resin) of the diffraction grating ispreferably within the range from 5 to 200 nm, more preferably within therange from 20 to 200 nm, and further preferably within the range from 50to 150 nm as described above.

In the diffraction grating produced according to the present inventionand the organic EL element including the diffraction grating, theaverage pitch of the concavities and convexities forming on the surface(the cured surface of curable resin) of the diffraction grating ispreferably within the range from 100 to 600 nm, and more preferablywithin the range from 200 to 600 nm as described above.

In the diffraction grating produced according to the present inventionand the organic EL element including the diffraction grating, accordingto the inventors' knowledge and perceptions, for the cross-section shapeof the concavity and convexity structure formed on the surface (thecured surface of curable resin) of the diffraction grating, an averagevalue m and a median M of a depth distribution of the concavities andconvexities on the cross-section obtained by a method which will bedescribed later preferably satisfy the following expression:

(1.062m−2.2533)×0.95≦M≦(1.062m−2.2533)×1.05

In a case that the median (M) and the average value (m) satisfy theabove expression, it is considered that generation of leakage currentcan be suppressed sufficiently when the diffraction grating is used forthe organic EL element etc.

In the diffraction grating produced according to the present inventionand the organic EL element including the diffraction grating, a kurtosisof the cross-section shape of the concavity and convexity structureformed on the surface (the surface of cured curable resin) of thediffraction grating is preferably −1.2 or more, and more preferably −1.2to 1.2. In a case that the kurtosis is less than the lower limit, theleakage current is more likely to be generated when the diffractiongrating is used for the organic EL element. In a case that the kurtosisexceeds the upper limit, the concavities and convexities on the surface(resin layer) of the diffraction grating are decreased. As a result, itis considered to cause the following situation. That is, not only thediffraction effect cannot be obtained sufficiently, but also theelectric field is more likely to be concentrated on the portions of theprojections, so that leakage currents are more likely to be generated.The kurtosis and a method for measuring the kurtosis will be describedlater on.

EXAMPLES

Hereinafter, the present invention will be described in detail byExamples and Comparative Examples. However, the present invention is notlimited to Examples below.

At first, an explanation will be made about five block copolymers usedin Examples and Comparative examples described below. Regarding any offive block copolymers, polystyrene (hereinafter referred to as “PS” inan abbreviated manner as appropriate) was used as the first polymersegment, and polymethyl methacrylate (hereinafter referred to as “PMMA”in an abbreviated manner as appropriate) was used as the second polymersegment. The volume ratio of the first polymer segment and secondpolymer segment (the first polymer segment: the second polymer segment)in each block copolymer was calculated on the assumption that thedensity of polystyrene was 1.05 g/cm³, the density of polymethylmethacrylate was 1.19 g/cm³. The number average molecular weights (Mn)and the weight average molecular weights (Mw) of polymer segments orpolymers were measured by using gel permeation chromatography (Model No:“GPC-8020” manufactured by Tosoh Corporation, in which TSK-GELSuperH1000, SuperH2000, SuperH3000, and SuperH4000 were connected inseries). The glass transition temperatures (Tg) of polymer segments weremeasured by use of a differential scanning calorimeter (manufactured byPerkin-Elmer under the product name of “DSC7”), while the temperaturewas raised at a rate of temperature rise of 20 degrees Celsius/min overa temperature range from 0 to 200 degrees Celsius. The solubilityparameters of polystyrene and polymethyl methacrylate were 9.0 and 9.3,respectively (see Kagaku Binran Ouyou Hen (Handbook of Chemistry,Applied Chemistry), 2nd edition).

Block copolymer 1 (hereinafter referred to as “BCP-1” in an abbreviatedmanner as appropriate)A block copolymer of PS and PMMA (manufactured by Polymer Source Inc.)Mn of PS segment=868,000Mn of PMMA segment=857,000Mn of block copolymer=1,725,000Volume ratio between PS segment and PMMA segment (PS:PMMA)=53:47Molecular weight distribution (Mw/Mn)=1.30Tg of PS segment=96 degrees CelsiusTg of PMMA segment=110 degrees CelsiusBlock copolymer 2 (hereinafter referred to as “BCP-2” in an abbreviatedmanner as appropriate)A block copolymer of PS and PMMA (manufactured by Polymer Source Inc.)Mn of PS segment=750,000Mn of PMMA segment=720,000Mn of block copolymer=1,470,000Volume ratio between PS segment and PMMA segment (PS:PMMA)=54:46Molecular weight distribution (Mw/Mn)=1.21Tg of PS segment=107 degrees CelsiusTg of PMMA segment=134 degrees CelsiusBlock copolymer 3 (hereinafter referred to as “BCP-3” in an abbreviatedmanner as appropriate)A block copolymer of PS and PMMA (manufactured by Polymer Source Inc.)Mn of PS segment=500,000,Mn of PMMA segment=480,000Mn of block copolymer=980,000Volume ratio between PS segment and PMMA segment (PS:PMMA)=54:46Molecular weight distribution (Mw/Mn)=1.18Tg of PS segment=107 degrees CelsiusTg of PMMA segment=134 degrees CelsiusBlock copolymer 4 (hereinafter referred to as “BCP-4” in an abbreviatedmanner as appropriate)A block copolymer of PS and PMMA (manufactured by Polymer Source Inc.)Mn of PS segment=270,000Mn of PMMA segment=289,000Mn of block copolymer=559,000Volume ratio between PS segment and PMMA segment (PS:PMMA)=51:49Molecular weight distribution (Mw/Mn)=1.18Tg of PS segment=110 degrees CelsiusTg of PMMA segment=124 degrees CelsiusBlock copolymer 5 (hereinafter referred to as “BCP-5” in an abbreviatedmanner as appropriate)A block copolymer of PS and PMMA (manufactured by Polymer Source Inc.)Mn of PS segment=133,000Mn of PMMA segment=130,000Mn of block copolymer=263,000Volume ratio between PS segment and PMMA segment (PS:PMMA)=54:46Molecular weight distribution (Mw/Mn)=1.15Tg of PS segment=110 degrees CelsiusTg of PMMA segment=124 degrees Celsius

Example 1

Toluene was added to 150 mg of the block copolymer 1 and 38 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. (Mw=3000, Mw/Mn=1.10) as polyethylene oxide so that the totalamount thereof was 10 g, followed by dissolving them. Then, the solutionwas filtrated or filtered through a membrane filter having a porediameter of 0.5 μm to obtain a block copolymer solution. The obtainedblock copolymer solution was applied, on a polyphenylene sulfide film(TORELINA manufactured by TORAY INDUSTRIES, INC.) as a base member, in afilm thickness of 200 to 250 nm, by a spin coating. The spin coating wasperformed at a spin speed of 500 rpm for 10 seconds, and then performedat a spin speed of 800 rpm for 30 seconds. The thin film applied by thespin coating was left at a room temperature for 10 minutes until thethin film was dried.

Subsequently, the base member on which the thin film was formed washeated for 5 hours in an oven of 170 degrees Celsius (first annealingprocess). Concavities and convexities were observed on the surface ofthe heated thin film, and it was found out that micro phase separationof the block copolymer forming the thin film was caused. Thecross-section of the thin film was observed with a transmission electronmicroscope (TEM) (H-7100FA manufactured by Hitachi, Ltd.). As shown inthe micrograph, of FIG. 5A, obtained by the transmission electronmicroscope, as a result of RuO4 staining, PS portions look black andPMMA portions look white.

The heated thin film as described above was subjected to an etchingprocess as described below to selectively decompose and remove PMMA onthe base member. The thin film was irradiated with ultraviolet rays atan irradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetic acid, and was subjectedto cleaning with ion-exchanged water, followed by being dried. As aresult, there was formed, on the base member, a concavity and convexitypattern clearly deeper than the concavities and convexities whichappeared on the surface of the thin film by the heating process.

Next, the base member was subjected to a heating process (secondannealing process) for 1 hour in an oven of 140 degrees Celsius so thatthe concavity and convexity pattern formed by the etching process wasdeformed to have a chevron-shaped structure (process for forming a shapeof chevrons).

About 10 nm of a thin nickel layer was formed as a current seed layer bya sputtering on the surface of the thin film, for which the process forforming the shape of chevrons had been performed. Subsequently, the basemember with the thin film was subjected to an electroforming process(maximum current density: 0.05 A/cm²) in a nickel sulfamate bath at atemperature of 50 degrees Celsius to precipitate nickel until thethickness of nickel became 250 μm. The base member Chemisol with thethin film was mechanically peeled off from the nickel electroformingbody obtained as described above. Subsequently, the nickelelectroforming body was immersed in Chemisol 2303 manufactured by TheJapan Cee-Bee Chemical Co., Ltd., followed by being cleaned while beingstirred for 2 hours at 50 degrees Celsius. Thereafter, polymercomponent(s) adhered to a part of the surface of the electroforming bodywas(were) removed by repeating the following process three times. Thatis, an acrylic-based UV curable resin was applied on the nickelelectroforming body; and the applied acrylic-based UV curable resin wascured; and then the cured resin was peeled off.

The cross-section of the nickel electroforming body from which thepolymer component was removed was observed with a scanning electronmicroscope (FE-SEM: S4800 manufactured by Hitachi, Ltd.). Theobservation is shown in FIG. 5B (magnifying magnification: 100-thousandtimes). It was understood from FIG. 5B that concavities and convexitiesof the nickel electroforming body were smooth and the cross-section ofeach convex portion had a smooth chevron shape having no overhang.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which mold-releasetreatment had been performed was obtained.

Subsequently, a fluorine-based UV curable resin was applied on a PETsubstrate (COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). Then,the fluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm², with the obtained nickel mold beingpressed thereto. After curing of the resin, the nickel mold was peeledoff from the cured resin. Accordingly, a diffraction grating made of thePET substrate with the resin film to which the surface profile of thenickel mold was transferred was obtained.

An analysis image of the concavity and convexity shape on the surface ofthe resin in the diffraction grating was obtained by using an atomicforce microscope (a scanning probe microscope equipped with anenvironment control unit “Nanonavi II Station/E-sweep” manufactured bySII NanoTechnology Inc.). Analysis conditions of the atomic forcemicroscope were as follows. Measurement mode: dynamic force mode

Cantilever: SI-DF40 (material: Si, lever width: 40 diameter of tip ofchip: 10 nm)Measurement atmosphere: in airMeasurement temperature: 25 degrees Celsius

FIG. 5E shows a concavity and convexity analysis image of the surface ofthe resin of the obtained diffraction grating. For comparison, FIG. 5Cshows a concavity and convexity analysis image of the concavity andconvexity pattern of the block copolymer from which PMMA was selectivelyremoved by the etching process, and FIG. 5D shows a concavity andconvexity analysis image of the concavity and convexity pattern of themold formed by the electroforming. The pattern shown in FIG. 5D was apattern transferred from the pattern shown in FIG. 5C, and thus thepattern shown in FIG. 5D was the inverted pattern of the pattern shownin FIG. 5C. It was found out that patterns of FIGS. 5C, 5D, and 5E had acommon pattern regularity and/or common pattern pitch, and that theconcavity and convexity pattern of the block copolymer from which PMMAwas selectively removed by the etching process was satisfactorilyreflected by the electroforming and the transfer to the resin to bethereafter performed.

FIG. 5F shows a concavity and convexity analysis image of thecross-section in the vicinity of the surface of the resin of theobtained diffraction grating. From the concavity and convexity analysisimages of the diffraction grating as shown in FIGS. 5E and 5F, Each ofan average height of the concavities and convexities, an average pitchof the concavities and convexities, a Fourier-transformed image, anaverage value and a median of a depth distribution of the concavitiesand convexities, and a kurtosis of the concavities and convexities wasobtained by the following methods.

<Average Height of Concavities and Convexities>

A concavity and convexity analysis image was obtained as described aboveby performing a measurement in a randomly selected measuring region of 3μm square (length: 3 μm, width: 3 μm) in the diffraction grating.Distances between randomly selected concave portions and convex portionsin the depth direction were measured at 100 points or more in theconcavity and convexity analysis image, and the average of the distanceswas calculated as the average height (depth) of the concavities andconvexities. The average height of the concavity and convexity patternin the analysis image obtained in this example was 62 nm.

<Average Pitch of Concavities and Convexities>

A concavity and convexity analysis image was obtained as described aboveby performing a measurement in a randomly selected measuring region of 3μm square (length: 3 μm, width: 3 μm) in the diffraction grating.Distances between randomly selected adjacent convex portions or betweenrandomly selected adjacent concave portions were measured at 100 pointsor more in the concavity and convexity analysis image, and the averageof the distances was calculated as the average pitch of the concavitiesand convexities. The average pitch of the concavity and convexitypattern in the analysis image obtained in this example was 480 nm.

<Fourier-Transformed Image>

A concavity and convexity analysis image was obtained as described aboveby performing a measurement in a randomly selected measuring region of 3μm square (length: 3 μm, width: 3 μm) in the diffraction grating. Theobtained concavity and convexity analysis image was subjected to aflattening process including primary inclination correction, and then totwo-dimensional fast Fourier transform processing. Thus, aFourier-transformed image was obtained. FIG. 5G shows the obtainedFourier-transformed image. As is clear from the result shown in FIG. 5G,it was confirmed that the Fourier-transformed image showed a circularpattern substantially centered at an origin at which an absolute valueof wavenumber was 0 μm⁻, and that the circular pattern was presentwithin a region where the absolute value of wavenumber was within arange of 10 μm⁻¹ or less.

The circular pattern of the Fourier-transformed image is a patternobserved due to gathering of bright spots in the Fourier-transformedimage. The term “circular” herein means that the pattern of thegathering of the bright spots looks like a substantially circular shape,and is a concept further including a case where a part of a contourlooks like a convex shape or a concave shape. The gathering of thebright spots may look like a substantially annular shape, and this caseis expressed as the term “annular”. It is noted that the term “annular”is a concept further including a case where a shape of an outer circleor inner circle of the ring looks like a substantially circular shapeand further including a case where a part of the contours of the outercircle and/or the inner circle of the ring looks like a convex shape ora concave shape. Further, the phrase “the circular or annular pattern ispresent within a region where an absolute value of wavenumber is withina range of 10 μm⁻¹ or less (more preferably from 1.25 to 10 μm⁻¹,further preferably from 1.25 to 5 μm⁻¹)” means that 30% or more (morepreferably 50% or more, further more preferably 80% or more, andparticularly preferably 90% or more) of bright spots forming theFourier-transformed image are present within a region where the absolutevalue of wavenumber is within a range of 10 μm⁻¹ or less (morepreferably from 1.25 to 10 μm⁻¹, and further preferably from 1.25 to 5μm⁻¹).

The two-dimensional fast Fourier transform processing on the concavityand convexity analysis image can be easily performed by electronic imageprocessing using a computer equipped with software for two-dimensionalfast Fourier transform processing.

<Average Value and Median of Depth Distribution of Concavities andConvexities>

A concavity and convexity analysis image was obtained by performing ameasurement in a randomly selected measuring region of 3 μm square(length: 3 μm, width: 3 μm) in the diffraction grating. Here, data ofeach of the heights of the concavities and convexities was determined at16384 (128 columns×128 rows) or more measuring points in the measuringregion on the nanometer scale. By using E-sweep in this example, ameasurement at 65536 points (256 columns×256 rows) (a measurement with aresolution of 256 pixels×256 pixels) was conducted in a measuring regionof 3 μm square. Regarding the thus measured heights (unit: nm) of theconcavities and convexities, first, a measuring point P which had thelargest height from the surface of the substrate among all the measuringpoints was determined. Then, while a plane which included the measuringpoint P and was parallel to the surface of the substrate was taken as areference plane (horizontal plane), values of depths from the referenceplane (the differences each obtained by subtracting the height from thesubstrate at one of the measuring points from the value of the heightfrom the substrate at the measuring point P) were determined asconcavity and convexity depth data. The concavity and convexity depthdata could be determined by automatic calculation with software providedin E-sweep. The values determined by automatic calculation could be usedas the concavity and convexity depth data. After the concavity andconvexity depth data was determined at each measuring point as describedabove, the average value (m) of the depth distribution of theconcavities and convexities could be determined by calculation accordingto the following formula (I):

$\begin{matrix}{m = {\frac{1}{N}{\sum\limits_{i = 1}^{N}x_{i}}}} & (I)\end{matrix}$

In the formula (I), N represents a total number of measuring points (thenumber of all the pixels), i represents any integer of 1 to N, x_(i)represents the concavity and convexity depth data at the i-th measuringpoint, and m represents the average value of the depth distribution ofthe concavities and convexities. Further, the median (M) of the depthdistribution of the concavities and convexities could be determined asfollows. The concavity and convexity depth data x_(i) at all the 1 toN-th measuring points were rearranged in ascending order, and expressedas x_((i)) (in this case, the order of the heights was as follows:x₍₁₎<x₍₂₎<x₍₃₎< . . . <x_((N))). Then, the median (M) could bedetermined by calculation according to one of the following formulae(II) depending on whether N was an odd number or an even number:

$\begin{matrix}\left. \begin{matrix}\begin{matrix}\left( {{In}\mspace{14mu} a\mspace{14mu} {case}\mspace{14mu} {where}\mspace{14mu} N\mspace{14mu} {was}\mspace{14mu} {odd}\mspace{14mu} {number}} \right) \\{M = x_{({{({N + 1})}/2})}}\end{matrix} \\\left( {{In}\mspace{14mu} a\mspace{14mu} {case}\mspace{14mu} {where}\mspace{14mu} N\mspace{14mu} {was}\mspace{14mu} {even}\mspace{14mu} {number}} \right) \\{M = \frac{x_{({N/2})} + x_{({{({N/2})} + 1})}}{2}}\end{matrix} \right\} & ({II})\end{matrix}$

In the formulae (II), N represents the total number of measuring points(the number of all the pixels), and M represents the median of the depthdistribution of the concavities and convexities. The average value (m)of the depth distribution of the concavities and convexities in thediffraction grating obtained in this example was 52.21 nm and the median(M) of the depth distribution of the concavities and convexities was57.00 nm.

<Kurtosis of Concavities and Convexities>

Similar to the method for measuring the median (M) of the depthdistribution and the average value (m) of the depth distribution, dataof each of the heights of the concavities and convexities was determinedat 16384 (128 columns×128 rows) or more measuring points in themeasuring region of 3 μm square. In this example, a measurement wasperformed adopting 65536 measuring points (256 columns×256 rows).Thereafter, the average value (m) of the depth distribution of theconcavities and convexities and the standard deviation (σ) of the depthdistribution of the concavities and convexities were calculated on thebasis of the concavity and convexity depth data of the measuring points.Note that, the average value (m) could be determined by calculationaccording to the above-described formula (I) as described above.Meanwhile, the standard deviation (σ) of the depth distribution could bedetermined by calculation according to the following formula (III):

$\begin{matrix}{\sigma = \sqrt{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {x_{i} - m} \right)^{2}}}} & ({III})\end{matrix}$

In the formula (III), N represents a total number of measuring points(the number of all the pixels), x_(i) represents the concavity andconvexity depth data at the i-th measuring point, and m represents theaverage value of the depth distribution of the concavities andconvexities. Subsequently, on the basis of the thus determined values ofthe average value (m) and the standard deviation (σ), the kurtosis (k)could be determined by calculation according to the following formula(IV):

$\begin{matrix}{k = {\frac{\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {x_{i} - m} \right)^{4}}}{\sigma^{4}} - 3}} & ({IV})\end{matrix}$

In formula (IV), N represents the total number of measuring points (thenumber of all the pixels), x_(i) represents the concavity and convexitydepth data at the i-th measuring point, m represents the average valueof the depth distribution of the concavities and convexities, and arepresents a value of the standard deviation. The Kurtosis ofconcavities and convexities in the diffraction grating obtained in thisexample was −0.546.

<Manufacture of Organic EL Element>

On the UV curable resin film as the diffraction grating obtained asdescribed above, a transparent electrode (ITO, thickness: 120 nm), ahole transporting layer(N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine,thickness: 40 nm), an electron transporting layer (8-hydroxyquinolinealuminum, thickness: 30 nm), a lithium fluoride layer (thickness: 1.5nm), and a metal electrode (aluminum, thickness: 100 nm) were eachstacked by a vapor deposition method to maintain the shape of theconcavities and convexities formed on the surface of the cured resinlayer. Accordingly, the organic EL element having a structure as shownin FIG. 4 was obtained.

Example 2

Toluene was added to 120 mg of the block copolymer 2 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.

Subsequently, 0.7 g of octadecyldimethylchlorosilane (ODS) was added to500 ml of heptane, followed by being stirred to prepare 2.0 mM of ODSsolution. A glass substrate after cleaning having a thickness of 1.1 mmwas immersed in the solution and stationarily placed for 24 hours. Thisprocessed substrate was subjected to ultrasonic cleaning with chloroformfor 10 minutes and then subjected to ultrasonic cleaning with pure waterfor 10 minutes, followed by being dried. Accordingly, an ODS-processedglass substrate was obtained.

The obtained block copolymer solution was applied, on the ODS-processedglass substrate, in a film thickness of 200 to 250 nm, by a spin coatingto form a thin film. The spin coating was performed at a spin speed of500 rpm for 10 seconds, and then performed at a spin speed of 800 rpmfor 30 seconds. After the spin coating, the thin film was left at a roomtemperature for 10 minutes until the thin film was dried.

Subsequently, the substrate was heated for 3 hours in an oven of 160degrees Celsius (first annealing process). It was observed thatconcavities and convexities were formed on the thin film on the surfaceof the heated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the substrate was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

The base member was subjected to a heating process (second annealingprocess) for 3 hours in an oven of 125 degrees Celsius so that the thinfilm was subjected to a process for forming a shape of chevrons.

Subsequently, about 10 nm of a thin nickel layer was formed on thesurface of the thin film by a sputtering. Then, the base member wassubjected to an electroforming process under the same condition asExample 1 in a nickel sulfamate bath to precipitate nickel until thethickness of nickel became 250 μm. The base member on which the nickelwas deposited as described above was mechanically peeled off from thenickel electroforming body. The nickel electroforming body from whichthe base member was peeled off was immersed in Chemisol 2303manufactured by The Japan Cee-Bee Chemical Co., Ltd., followed by beingcleaned while being stirred for 2 hours at 50 degrees Celsius.Thereafter, the nickel electroforming body was immersed in atetrahydrofuran solution and an ultrasonic cleaning process was carriedout for 30 minutes. Polymer component(s), adhered to a part of thesurface of the electroforming body, which was(were) visually confirmedwas(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained.

Subsequently, a fluorine-based UV curable resin was applied on a PETsubstrate (COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). Afterthe nickel mold was pressed against the fluorine-based UV curable resin,the fluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm² and then the nickel mold was peeled off.Accordingly, a UV curable resin film to which the surface profile of thenickel mold was transferred was obtained. Again, the fluorine-based UVcurable resin was applied on a PET substrate (COSMOSHINE A-4100manufactured by Toyobo Co., Ltd.). After the UV curable resin film waspressed against the fluorine-based UV curable resin, the fluorine-basedUV curable resin was cured by irradiation with ultraviolet rays at 600mJ/cm² and then the UV curable resin film was peeled off. Accordingly, asecond UV curable resin film was obtained. Further, the fluorine-basedUV curable resin was applied on a glass for which a silane couplingprocess had been performed. After the second UV curable resin film waspressed against the fluorine-based UV curable resin, the fluorine-basedUV curable resin was cured by irradiation with ultraviolet rays at 600mJ/cm² and then the second UV curable resin film was peeled off.Accordingly, a diffraction grating in which a pattern was formed on theglass substrate was obtained. For the concavity and convexity pattern ofthe diffraction grating, the concavity and convexity shape on thesurface was analyzed by using the atomic force microscope in the samemanner as Example 1 to obtain an analysis image. Analysis conditions ofthe atomic force microscope were the same as those in Example 1.

FIG. 6D shows the obtained concavity and convexity analysis image. Forcomparison, FIG. 6A shows a concavity and convexity analysis image ofthe concavity and convexity pattern of the block copolymer from whichPMMA was selectively removed by the etching process; FIG. 6B shows aconcavity and convexity analysis image of the concavity and convexitypattern for which the process for forming the shape of chevrons wasperformed in the second anneal step after the etching process; and FIG.6C shows a concavity and convexity analysis image of the concavity andconvexity pattern of the mold formed by the electroforming. The patternshown in FIG. 6C was the inverted pattern of those shown in FIGS. 6A,6B, and 6D. It was found out that patterns of FIGS. 6A, 6B, 6C, and 6Dhad a common pattern regularity and/or common pattern pitch, and thatthe planar shape of the concavity and convexity pattern of the blockcopolymer from which PMMA was selectively removed by the etching processwas satisfactorily reflected by the second heating, the electroforming,and the transfer to the resin to be thereafter performed.

FIG. 6E shows a concavity and convexity analysis image of thecross-section in the vicinity of the surface of the obtained diffractiongrating. From the analysis images (FIGS. 6D and 6E) of the surfaces ofthe diffraction grating, an average height of the concavities andconvexities, an average pitch of the concavities and convexities, anaverage value (m) and a median (M) of a depth distribution of theconcavities and convexities, and a kurtosis of the concavities andconvexities of the diffraction grating were each obtained in the samemanner as Example 1. The results thereof are described as follows.

Average height: 55 nmAverage pitch: 320 nmAverage value (m) of depth distribution: 44.93 nmMedian (M) of depth distribution: 45.7 nm

Kurtosis: −1.13

FIG. 6F shows a Fourier-transformed image obtained from the analysisimages. As is apparent from the result shown in FIG. 6F, it was observedthat the Fourier-transformed image showed a circular patternsubstantially centered at an origin at which an absolute value ofwavenumber was 0 μm⁻¹, and that the circular pattern was present withina region where the absolute value of wavenumber was within a range of 10μm⁻¹ or less.

<Manufacture of Organic EL Element>

On the glass substrate with the pattern made of the fluorine-based UVcurable resin as the diffraction grating obtained as described above, atransparent electrode (ITO, thickness: 120 nm), a hole transportinglayer(N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine,thickness: 40 nm), an electron transporting layer (8-hydroxyquinolinealuminum, thickness: 30 nm), a lithium fluoride layer (thickness: 1.5nm), and a metal electrode (aluminum, thickness: 100 nm) were eachstacked by a vapor deposition method to maintain the shape of theconcavities and convexities formed on the surface of the cured resinlayer. Accordingly, the organic EL element was obtained.

<Evaluation of Light Emission Efficiency of Organic EL Element>

A light emission efficiency of the organic EL element obtained in thisexample was measured by the following method. That is, voltage wasapplied to the obtained organic EL element, and then the applied voltageV and current I flowing through the organic EL element were measuredwith a source measurement instrument (manufactured by ADC CORPORATION,R6244), and a total luminous flux amount L was measured with a totalflux measurement apparatus manufactured by Spectra Co-op. From the thusobtained measured value of the applied voltage V, the current I, and thetotal luminous flux amount L, a luminance value L′ was calculated. Here,for the current efficiency, the following calculation formula (F1) wasused:

Current efficiency=(L′/I)×S  (F1)

and, for the power efficiency, the following calculation formula (F2)was used:

Power efficiency=(L′/I/V)×S  (F2)

Accordingly, the current efficiency and the power efficiency of theorganic EL element were calculated. In the above formulae, S is alight-emitting or luminescent area of the organic EL element. FIG. 6Gshows a graph showing change of the current efficiency of the organic ELelement obtained by using the above formula with respect to theluminance L′. Further, FIG. 6H shows a graph showing change of the powerefficiency of the organic EL element calculated by using the aboveformula with respect to the luminance L′. In each of FIG. 6G and FIG.6H, square marks indicate results of this example and circular dotsindicate results of the organic EL element produced by stacking eachlayer on a glass substrate in which no concavity and convexity patternof the diffraction grating is formed, in the same manner as describedabove. Noted that the value of the luminance L′ was calculated on theassumption that light distribution characteristic of the organic ELelement followed Lambert's law. The following calculation formula (F3)was used:

L′=L/π/S  (F3)

From the result shown in FIG. 6G, it was found that the currentefficiency of the organic EL element of this example at a luminance of500 to 2000 cd/m² was about 2.5 times that of the organic EL elementhaving no concavity and convexity on the glass substrate. Further, fromthe result shown in FIG. 6H, it was found that the current efficiency ofthe organic EL element of this example at the luminance of 500 to 2000cd/m² was about 3 times that of the organic EL element having noconcavity and convexity on the glass substrate. Therefore, the organicEL element of the present invention had an external extractionefficiency sufficiently.

<Evaluation of Light Emission Directivity of Organic EL Element>

The directivity of light emission of the organic EL element obtained inthis example was evaluated by the following method. That is, the organicEL element in a luminescent state was visually observed in all thedirections (directions of all around 360°). Neither particularly brightsites nor particularly dark sites were observed when the organic ELelement obtained in Example 2 was observed in any of the directions ofall around 360°, and the brightness was uniform in all the directions.In this way, it was shown that the directivity of light emission of theorganic EL element of the present invention was sufficiently low.

Example 3

Toluene was added to 120 mg of the block copolymer 2 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.

Subsequently, 170 mg of methyltrimethoxysilane (MTMS) and 89 mg of1,2-bis(trimethoxysilyl)ethane (BTMSE) were added to 4.75 g ofmethylisobutylketone, followed by being stirred to preparemethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane solution. Thissolution was applied on a glass substrate after cleaning having athickness of 1.1 mm by a spin coating to obtain a glass substrate with acoating film made ofmethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane. The spin coatingwas performed at a spin speed of 500 rpm for 10 seconds, and thenperformed at a spin speed of 800 rpm for 30 seconds. The glass substratewith the coating film was sintered for 6 hours in a nitrogen atmosphereat a temperature of 280 degrees Celsius to obtain an organo silicateprocessed glass substrate.

The obtained block copolymer solution was applied, on the organosilicate processed glass substrate, in a film thickness of 200 to 250nm, by a spin coating, to form a thin film. The spin coating wasperformed at a spin speed of 500 rpm for 10 seconds, and then performedat a spin speed of 800 rpm for 30 seconds. After the spin coating, thethin film was left at a room temperature for 10 minutes until the thinfilm was dried.

Subsequently, the base member was heated for 6 hours in an oven of 160degrees Celsius (first annealing process). It was observed thatconcavities and convexities were formed on the thin film on the surfaceof the heated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the substrate was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

The base member was subjected to a heating process (second annealingprocess) for 1 hour in an oven of 125 degrees Celsius so that the thinfilm was subjected to a process for forming a shape of chevrons.

Subsequently, about 10 nm of a thin nickel layer was formed on thesurface of the thin film by a sputtering. Then, the base member wassubjected to an electroforming process under the same condition asExample 1 in a nickel sulfamate bath to precipitate nickel until thethickness of nickel became 250 μm. The base member on which the nickelwas deposited as described above was immersed in a tetrahydrofuransolution, and then the base member was peeled off from the nickelelectroforming body. The nickel electroforming body from which the basemember was peeled off was immersed in the tetrahydrofuran solution andan ultrasonic cleaning process was carried out for 30 minutes. Polymercomponent(s), adhered to a part of the surface of the electroformingbody, which was(were) visually confirmed was(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, afluorine-based UV curable resin was applied on a PET substrate(COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). After the nickelmold was pressed against the fluorine-based UV curable resin, thefluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm² and then the nickel mold was peeled off.Accordingly, a UV curable resin film to which the surface profile of thenickel mold was transferred was obtained. Further, the fluorine-based UVcurable resin was applied on a glass for which a silane coupling processhad been performed. After the UV curable resin film was pressed againstthe fluorine-based UV curable resin, the fluorine-based UV curable resinwas cured by irradiation with ultraviolet rays at 600 mJ/cm² and thenthe UV curable resin film was peeled off. Accordingly, a diffractiongrating formed of the glass substrate was obtained. For the concavityand convexity pattern of the diffraction grating, the concavity andconvexity shape on the surface was analyzed by using the atomic forcemicroscope used in Example 1 to obtain an analysis image. Analysisconditions of the atomic force microscope were the same as those inExample 1.

FIG. 7C shows the obtained concavity and convexity analysis image. Forcomparison, FIG. 7A shows a concavity and convexity analysis image ofthe concavity and convexity pattern of the block copolymer from whichPMMA was selectively removed by the etching process; and FIG. 7B shows aconcavity and convexity analysis image of the concavity and convexitypattern for which the process for forming the shape of chevrons wasperformed in the second anneal step after the etching process. It wasfound out that the patterns shown in FIGS. 7A, 7B, and 7C had a commonpattern regularity and/or common pattern pitch and that the planar shapeof the concavity and convexity pattern of the block copolymer from whichPMMA was selectively removed by the etching process was satisfactorilyreflected by the second heating process and the transfer of the mold tothe resin.

FIG. 7D shows a concavity and convexity analysis image of thecross-section in the vicinity of the surface of the obtained diffractiongrating. From the analysis images of the surfaces of the diffractiongrating, an average height of the concavities and convexities, anaverage pitch of the concavities and convexities, an average value (m)and a median (M) of a depth distribution of the concavities andconvexities, and a kurtosis of the concavities and convexities of thediffraction grating were each obtained in the same manner as Example 1.The results thereof are described as follows.

Average height: 61 nmAverage pitch: 310 nmAverage value (m) of depth distribution: 48.69 nmMedian (M) of depth distribution: 50.41 nm

Kurtosis: −1.17

FIG. 7E shows a Fourier-transformed image obtained from the analysisimages. As is apparent from the result shown in FIG. 7E, it was observedthat the Fourier-transformed image showed a circular patternsubstantially centered at an origin at which an absolute value ofwavenumber was 0 μm⁻¹, and that the circular pattern was present withina region where the absolute value of wavenumber was within a range of 10μm⁻¹ or less.

On the glass substrate with the concavities and convexities as thediffraction grating obtained as described above, a transparent electrode(ITO, thickness: 120 nm), a hole transporting layer(N,N′-diphenyl-N,N-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine,thickness: 40 nm), an electron transporting layer (8-hydroxyquinolinealuminum, thickness: 30 nm), a lithium fluoride layer (thickness: 1.5nm), and a metal electrode (aluminum, thickness: 100 nm) were eachstacked by a vapor deposition method to maintain the shape of theconcavities and convexities formed on the surface of the cured resinlayer. Accordingly, the organic EL element was obtained.

Example 4

Toluene was added to 120 mg of the block copolymer 3 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.

170 mg of methyltrimethoxysilane (MTMS) and 89 mg of1,2-bis(trimethoxysilyl)ethane (BTMSE) were added to 4.75 g ofmethylisobutylketone, followed by being stirred to preparemethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane solution. Thissolution was applied on a glass substrate after cleaning having athickness of 1.1 mm by a spin coating to obtain a glass substrate with acoating film made ofmethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane. The spin coatingwas performed at a spin speed of 500 rpm for 10 seconds, and thenperformed at a spin speed of 800 rpm for 30 seconds. Subsequently, theglass substrate with the coating film was sintered for 6 hours in anitrogen atmosphere at a temperature of 300 degrees Celsius to obtain anorgano silicate processed glass substrate.

The obtained block copolymer solution was applied, on the organosilicate processed glass substrate, in a film thickness of 200 to 250nm, by a spin coating. The spin coating was performed at a spin speed of500 rpm for 10 seconds, and then performed at a spin speed of 800 rpmfor 30 seconds. After the spin coating, the thin film was left at a roomtemperature for 10 minutes until the thin film was dried.

Subsequently, the substrate was heated for 6 hours in an oven of 160degrees Celsius (first annealing process). It was observed thatconcavities and convexities were formed on the thin film on the surfaceof the heated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the substrate was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

The base member was subjected to a heating process (second annealingprocess) for 1 hour in an oven of 125 degrees Celsius so that the thinfilm was subjected to a process for forming a shape of chevrons.

Subsequently, about 10 nm of a thin nickel layer was formed on thesurface of the thin film by a sputtering. Then, the base member wassubjected to an electroforming process under the same condition asExample 1 in a nickel sulfamate bath to precipitate nickel until thethickness of nickel became 250 μm. The base member on which the nickelwas deposited as described above was mechanically peeled off from thenickel electroforming body. Then, the following process was repeatedthree times. An acrylic-based UV curable resin was applied on the nickelelectroforming body from which the base member was peeled off; theapplied acrylic-based UV curable resin was cured; and then the curedresin was peeled off. Further, the nickel electroforming body wasimmersed in Chemizol 2303 manufactured by The Japan Cee-Bee ChemicalCo., Ltd., followed by being cleaned while being stirred for 2 hours ata temperature of 50 degrees Celsius. Accordingly, polymer component(s),adhered to a part of the surface of the electroforming body, whichwas(were) visually confirmed was(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, asilicone-based polymer [a resin composition of a mixture of 90% by massof a silicone rubber (manufactured by Wacker Chemie AG under the productname of “Elastosil RT601”) and 10% by mass of a curing agent] wasapplied onto the nickel mold by a dropping method, then cured by beingheated at 50 degrees Celsius for 1 hour, and thereafter detached fromthe nickel mold. Thus, a silicone rubber to which the surface profile ofthe nickel mold was transferred was obtained. Further, a fluorine-basedUV curable resin was applied on a glass for which a silane couplingprocess had been performed. After the silicone rubber was pressedagainst the fluorine-based UV curable resin, the fluorine-based UVcurable resin was cured by irradiation with ultraviolet rays at 600mJ/cm² and then the silicone rubber was peeled off. Accordingly, adiffraction grating formed of the glass substrate, in which theconcavity and convexity pattern of a fluorine-based resin was formed,was obtained.

For the concavity and convexity pattern of the diffraction grating, theconcavity and convexity shape on the surface was analyzed by using theatomic force microscope used in Example 1 to obtain an analysis image.Analysis conditions of the atomic force microscope were the same asthose in Example 1.

FIG. 8C shows the obtained concavity and convexity analysis image. Forcomparison, FIG. 8A shows a concavity and convexity analysis image ofthe concavity and convexity pattern of the block copolymer from whichPMMA was selectively removed by the etching process; and FIG. 8B shows aconcavity and convexity analysis image of the concavity and convexitypattern for which the process for forming the shape of chevrons wasperformed in the second anneal step after the etching process. It wasfound out that the patterns shown in FIGS. 8A, 8B, and 8C had a commonpattern regularity and/or common pattern pitch and that the planar shapeof the concavity and convexity pattern of the block copolymer from whichPMMA was selectively removed by the etching process was satisfactorilyreflected by the second annealing process and the transfer of the moldto the resin.

FIG. 8D shows a concavity and convexity analysis image of thecross-section in the vicinity of the surface of the obtained diffractiongrating. From the analysis images of the surfaces of the diffractiongrating, an average height of the concavities and convexities, anaverage pitch of the concavities and convexities, an average value (m)and a median (M) of a depth distribution of the concavities andconvexities, and a kurtosis of the concavities and convexities of thediffraction grating were each obtained in the same manner as Example 1.The results thereof are described as follows.

Average height: 58 nmAverage pitch: 300 nmAverage value (m) of depth distribution: 51.96 nmMedian (M) of depth distribution: 55.56 nm

Kurtosis: −1.142

FIG. 8E shows a Fourier-transformed image obtained from the analysisimages. As is apparent from the result shown in FIG. 8E, it was observedthat the Fourier-transformed image showed a circular patternsubstantially centered at an origin at which an absolute value ofwavenumber was 0 μm⁻¹, and that the circular pattern was present withina region where the absolute value of wavenumber was within a range of 10μm⁻¹ or less.

On the UV curable resin film as the diffraction grating obtained asdescribed above, a transparent electrode (ITO, thickness: 120 nm), ahole transporting layer(N,N-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine,thickness: 40 nm), an electron transporting layer (8-hydroxyquinolinealuminum, thickness: 30 nm), a lithium fluoride layer (thickness: 1.5nm), and a metal electrode (aluminum, thickness: 100 nm) were eachstacked by a vapor deposition method to maintain the shape of theconcavities and convexities formed on the surface of the cured resinlayer. Accordingly, the organic EL element was obtained.

<Evaluation of Light Emission Efficiency of Organic EL Element>

A light emission efficiency of the organic EL element obtained in thisexample was measured in the same manner as Example 2. FIG. 8F shows arelation between a current efficiency and a luminance L′ of the organicEL element; FIG. 8G shows a relation between a power efficiency and theluminance L′ of the organic EL element. In each of FIG. 8F and FIG. 8G,square marks indicate results of this example and circular dots indicateresults of the organic EL element produced by stacking each layer on aglass substrate in which the concavity and convexity pattern of thediffraction grating is not formed, in the same manner as describedabove. From the result shown in FIG. 8F, it was found that the currentefficiency of the organic EL element of this example at a luminance of500 to 2000 cd/m² was more than twice that of the organic EL elementhaving no concavity and convexity on the glass substrate. Further, fromthe result shown in FIG. 8G, it was found that the current efficiency ofthe organic EL element of this example at the luminance of 500 to 2000cd/m² was about 3 times that of the organic EL element having noconcavity and convexity on the glass substrate. Therefore, the organicEL element of the present invention had an external extractionefficiency sufficiently.

<Evaluation of Light Emission Directivity of Organic EL Element>

The directivity of light emission of the organic EL element obtained inthis example was evaluated in the similar manner as Example 2. That is,the organic EL element in a luminescent state was visually observed inall the directions (directions of all around 360°). Neither particularlybright sites nor particularly dark sites were observed when the organicEL element obtained in Example 4 was observed in any of the directionsof all around 360°, and the brightness was uniform in all thedirections. In this way, it was shown that the directivity of lightemission of the organic EL element of the present invention wassufficiently low.

Example 5

Toluene was added to 150 mg of the block copolymer 4 and 23 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.

Subsequently, 0.7 g of octadecyl trichlorosilane (OTS) was added to 500ml of heptane, followed by being stirred to prepare 2.0 mM of OTSsolution. A glass substrate after cleaning having a thickness of 1.1 mmwas immersed in the solution and stationarily placed for 24 hours. Thisprocessed substrate was subjected to ultrasonic cleaning with chloroformfor 10 minutes and then subjected to ultrasonic cleaning with pure waterfor 10 minutes, followed by being dried. Accordingly, an OTS-processedglass substrate was obtained.

The obtained block copolymer solution was applied, on the OTS-processedglass substrate, in a film thickness of 200 to 250 nm, by a spincoating. The spin coating was performed at a spin speed of 500 rpm for10 seconds, and then performed at a spin speed of 800 rpm for 30seconds. After the spin coating, the thin film was left at a roomtemperature for 10 minutes until the thin film was dried.

Subsequently, the base member was heated for 8 hours in an oven of 150degrees Celsius (first annealing process). It was observed thatconcavities and convexities were formed on the thin film on the surfaceof the heated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the base member was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

The base member was subjected to a heating process (second annealingprocess) for 1 hour in an oven of 125 degrees Celsius so that the thinfilm was subjected to a process for forming a shape of chevrons.

Subsequently, about 30 nm of a thin nickel layer was formed on thesurface of the thin film by a vapor deposition method. Then, the basemember was subjected to an electroforming process under the samecondition as Example 1 in a nickel sulfamate bath to precipitate nickeluntil the thickness of nickel became 250 μm. The base member on whichthe nickel was deposited as described above was mechanically peeled offfrom the nickel electroforming body. Then, the following process wasrepeated three times. An acrylic-based UV curable resin was applied onthe nickel electroforming body from which the base member was peeledoff; the applied acrylic-based UV curable resin was cured; and then thecured resin was peeled off. Further, the nickel electroforming body wasimmersed in Chemisol 2303 manufactured by The Japan Cee-Bee ChemicalCo., Ltd., followed by being cleaned while being stirred for 2 hours at50 degrees Celsius. Accordingly, polymer component(s), adhered to a partof the surface of the electroforming body, which was(were) visuallyconfirmed was(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, afluorine-based UV curable resin was applied on a PET substrate(COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). After the nickelmold was pressed against the fluorine-based UV curable resin, thefluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm² and then the nickel mold was peeled off.Accordingly, a diffraction grating made of a UV curable resin film towhich the surface profile of the nickel mold was transferred wasobtained. For the concavity and convexity pattern of the diffractiongrating, the concavity and convexity shape on the surface was analyzedby using the atomic force microscope used in Example 1 to obtain ananalysis image. Analysis conditions of the atomic force microscope werethe same as those in Example 1.

FIG. 9A shows the obtained concavity and convexity analysis image.Further, FIG. 9B shows the obtained concavity and convexity analysisimage of the cross-section. From the analysis images, an average heightof the concavities and convexities, an average pitch of the concavitiesand convexities, an average value (m) and a median (M) of a depthdistribution of the concavities and convexities, and a kurtosis of theconcavities and convexities were each obtained in the same manner asExample 1.

The results thereof are described as follows.Average height: 40 nmAverage pitch: 110 nmAverage value (m) of depth distribution: 59.84 nmMedian (M) of depth distribution: 61.06 nm

Kurtosis: 0.729

FIG. 9C shows a Fourier-transformed image obtained from the analysisimages. As is apparent from the result shown in FIG. 9C, it was observedthat the Fourier-transformed image showed a circular patternsubstantially centered at an origin at which an absolute value ofwavenumber was 0 μm⁻¹, and that the circular pattern was present withina region where the absolute value of wavenumber was within a range of 10μm⁻¹ or less.

On the UV curable resin film as the diffraction grating obtained asdescribed above, a transparent electrode (ITO, thickness: 120 nm), ahole transporting layer(N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine,thickness: 40 nm), an electron transporting layer (8-hydroxyquinolinealuminum, thickness: 30 nm), a lithium fluoride layer (thickness: 1.5nm), and a metal electrode (aluminum, thickness: 100 nm) were eachstacked by a vapor deposition method to maintain the shape of theconcavities and convexities formed on the surface of the cured resinlayer. Accordingly, the organic EL element was obtained.

Example 6

Toluene was added to 120 mg of the block copolymer 2 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.

Subsequently, 170 mg of methyltrimethoxysilane (MTMS) and 89 mg of1,2-bis(trimethoxysilyl)ethane (BTMSE) were added to 4.75 g ofmethylisobutylketone, followed by being stirred to preparemethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane solution. Thissolution was applied on a glass substrate after cleaning having athickness of 1.1 mm by a spin coating to obtain a glass substrate with acoating film made ofmethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane. The spin coatingwas performed at a spin speed of 500 rpm for 10 seconds, and thenperformed at a spin speed of 800 rpm for 30 seconds. Thereafter, theglass substrate with the coating film was sintered for 6 hours in anitrogen atmosphere at a temperature of 280 degrees Celsius to obtain anorgano silicate processed glass substrate.

The obtained block copolymer solution was applied, on the organosilicate processed glass substrate, in a film thickness of 200 to 250nm, by a spin coating. The spin coating was performed at a spin speed of500 rpm for 10 seconds, and then performed at a spin speed of 800 rpmfor 30 seconds. After the spin coating, the thin film was left at a roomtemperature for 10 minutes until the thin film was dried.

Subsequently, the base member was heated for 5 hours in an oven of 160degrees Celsius (first annealing process). It was observed thatconcavities and convexities were formed on the thin film on the surfaceof the heated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the base member was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

The base member was subjected to a heating process (second annealingprocess) for 85 hours in an oven of 110 degrees Celsius so that the thinfilm was subjected to a process for forming a shape of chevrons.

Subsequently, about 10 nm of a thin nickel layer was formed on thesurface of the thin film by a sputtering. Then, the base member wassubjected to an electroforming process under the same condition asExample 1 in a nickel sulfamate bath to precipitate nickel until thethickness of nickel became 250 μm. The base member on which the nickelwas deposited as described above was mechanically peeled off from thenickel electroforming body. The nickel electroforming body from whichthe base member was peeled off was immersed in Chemisol 2303manufactured by The Japan Cee-Bee Chemical Co., Ltd., followed by beingcleaned while being stirred for 2 hours at 50 degrees Celsius.Thereafter, the nickel electroforming body was immersed in atetrahydrofuran solution and an ultrasonic cleaning process was carriedout for 30 minutes. Accordingly, polymer component(s), adhered to a partof the surface of the electroforming body, which was(were) visuallyconfirmed was(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, afluorine-based UV curable resin was applied on a PET substrate(COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). After the nickelmold was pressed against the fluorine-based UV curable resin, thefluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm² and then the nickel mold was peeled off.Accordingly, a diffraction grating made of the UV curable resin film towhich the surface profile of the nickel mold was transferred wasobtained. For the concavity and convexity pattern of the diffractiongrating, the concavity and convexity shape on the surface was analyzedby using the atomic force microscope used in Example 1 to obtain ananalysis image. Analysis conditions of the atomic force microscope werethe same as those in Example 1.

FIG. 10C shows the obtained concavity and convexity analysis image. Forcomparison, FIG. 10A shows a concavity and convexity analysis image ofthe concavity and convexity pattern of the block copolymer from whichPMMA was selectively removed by the etching process; and FIG. 10B showsa concavity and convexity analysis image of the concavity and convexitypattern of the mold formed by the electroforming. The pattern shown inFIG. 10B showed the inverted pattern, of the pattern shown in FIG. 10A,which was transferred from the pattern shown in FIG. 10A. From FIGS.10A, 10B, and 10C, it was found out that the patterns of FIGS. 10A, 10B,and 10C had a common pattern regularity and/or common pattern pitch andthat the planar shape of the concavity and convexity pattern of theblock copolymer from which PMMA was selectively removed by the etchingprocess was satisfactorily reflected by the electroforming and thetransfer of the mold to the resin.

FIG. 10D shows a concavity and convexity analysis image of thecross-section in the vicinity of the surface of the obtained diffractiongrating. From the analysis images of the surfaces of the diffractiongrating, an average height of the concavities and convexities, anaverage pitch of the concavities and convexities, an average value (m)and a median (M) of a depth distribution of the concavities andconvexities, and a kurtosis of the concavities and convexities of thediffraction grating were each obtained in the same manner as Example 1.The results thereof are described as follows.

Average height: 72 nmAverage pitch: 380 nmAverage value (m) of depth distribution: 61.43 nmMedian (M) of depth distribution: 63.69 nm

Kurtosis: −1.091

FIG. 10E shows a Fourier-transformed image obtained from the analysisimages. As is apparent from the result shown in FIG. 10E, it wasobserved that the Fourier-transformed image showed a circular patternsubstantially centered at an origin at which an absolute value ofwavenumber was 0 μm⁻¹, and that the circular pattern was present withina region where the absolute value of wavenumber was within a range of 10μm⁻¹ or less.

On the UV curable resin film as the diffraction grating obtained asdescribed above, a transparent electrode (ITO, thickness: 120 nm), ahole transporting layer(N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine,thickness: 40 nm), an electron transporting layer (8-hydroxyquinolinealuminum, thickness: 30 nm), a lithium fluoride layer (thickness: 1.5nm), and a metal electrode (aluminum, thickness: 100 nm) were eachstacked by a vapor deposition method to maintain the shape of theconcavities and convexities formed on the surface of the cured resinlayer. Accordingly, the organic EL element was obtained.

Example 7

Toluene was added to 120 mg of the block copolymer 2 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.

Subsequently, 170 mg of methyltrimethoxysilane (MTMS) and 89 mg of1,2-bis(trimethoxysilyl)ethane (BTMSE) were added to 4.75 g ofmethylisobutylketone, followed by being stirred to preparemethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane solution. Thissolution was applied on a glass substrate after cleaning having athickness of 1.1 mm by a spin coating to obtain a glass substrate with acoating film made ofmethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane. The spin coatingwas performed at a spin speed of 500 rpm for 10 seconds, and thenperformed at a spin speed of 800 rpm for 30 seconds. Thereafter, theglass substrate with the coating film was sintered for 6 hours in anitrogen atmosphere at a temperature of 280 degrees Celsius to obtain anorgano silicate processed glass substrate.

The obtained block copolymer solution was applied, on the organosilicate processed glass substrate, in a film thickness of 200 to 250nm, by a spin coating. The spin coating was performed at a spin speed of500 rpm for 10 seconds, and then performed at a spin speed of 800 rpmfor 30 seconds. After the spin coating, the thin film was left at a roomtemperature for 10 minutes until the thin film was dried.

Subsequently, the substrate was heated for 5 hours in an oven of 160degrees Celsius (annealing process). It was observed that concavitiesand convexities were formed on the thin film on the surface of theheated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the base member was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

The base member was subjected to a heating process (second annealingprocess) for 20 minutes in an oven of 170 degrees Celsius so that thethin film was subjected to a process for forming a shape of chevrons.

Subsequently, about 10 nm of a thin nickel layer was formed on thesurface of the thin film by a sputtering. Then, the base member wassubjected to an electroforming process under the same condition asExample 1 in a nickel sulfamate bath to precipitate nickel until thethickness of nickel became 250 μm. The base member on which the nickelwas deposited as described above was mechanically peeled off from thenickel electroforming body. The nickel electroforming body from whichthe base member was peeled off was immersed in Chemisol 2303manufactured by The Japan Cee-Bee Chemical Co., Ltd., followed by beingcleaned while being stirred for 2 hours at 50 degrees Celsius.Thereafter, the nickel electroforming body was immersed in atetrahydrofuran solution and an ultrasonic cleaning process was carriedout for 30 minutes. Accordingly, polymer component(s), adhered to a partof the surface of the electroforming body, which was(were) visuallyconfirmed was(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, afluorine-based UV curable resin was applied on the nickel mold. After aglass, for which a silane coupling process had been performed, waspressed against the fluorine-based UV curable resin, the fluorine-basedUV curable resin was cured by irradiation with ultraviolet rays at 600mJ/cm² and then the nickel mold was peeled off. Accordingly, adiffraction grating made of the glass substrate on which the concavityand convexity pattern of the fluorine-based resin, to which the surfaceprofile of the nickel mold was transferred, was formed was obtained. Forthe concavity and convexity pattern of the diffraction grating, theconcavity and convexity shape on the surface was analyzed by using theatomic force microscope used in Example 1 to obtain an analysis image.Analysis conditions of the atomic force microscope were the same asthose in Example 1.

FIG. 11B shows the obtained concavity and convexity analysis image. Forcomparison, FIG. 11A shows a concavity and convexity analysis image ofthe concavity and convexity pattern of the block copolymer from whichPMMA was selectively removed by the etching process. From FIGS. 11A and11B, it was found out that the patterns shown in FIGS. 11A and 11B had acommon pattern regularity and/or common pattern pitch and that theplanar shape of the concavity and convexity pattern of the blockcopolymer from which PMMA was selectively removed by the etching processwas satisfactorily reflected by the transfer of the mold to the resin.

FIG. 11C shows a concavity and convexity analysis image of thecross-section in the vicinity of the surface of the obtained diffractiongrating. From the analysis images of the surfaces of the diffractiongrating, an average height of the concavities and convexities, anaverage pitch of the concavities and convexities, an average value (m)and a median (M) of a depth distribution of the concavities andconvexities, and a kurtosis of the concavities and convexities of thediffraction grating were each obtained in the same manner as Example 1.The results thereof are described as follows.

Average height: 68 nmAverage pitch: 420 nmAverage value (m) of depth distribution: 49.88 nmMedian (M) of depth distribution: 54.27 nm

Kurtosis: −0.518

FIG. 11D shows a Fourier-transformed image obtained from the analysisimages. As is apparent from the result shown in FIG. 11D, it wasobserved that the Fourier-transformed image showed a circular patternsubstantially centered at an origin at which an absolute value ofwavenumber was 0 μm⁻¹, and that the circular pattern was present withina region where the absolute value of wavenumber was within a range of 10μm⁻¹ or less.

On the UV curable resin film as the diffraction grating obtained asdescribed above, a transparent electrode (ITO, thickness: 120 nm), ahole transporting layer(N,N′-diphenyl-N,N-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine,thickness: 40 nm), an electron transporting layer (8-hydroxyquinolinealuminum, thickness: 30 nm), a lithium fluoride layer (thickness: 1.5nm), and a metal electrode (aluminum, thickness: 100 nm) were eachstacked by a vapor deposition method to maintain the shape of theconcavities and convexities formed on the surface of the cured resinlayer. Accordingly, the organic EL element was obtained.

Example 8

Toluene was added to 120 mg of the block copolymer 1 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.The obtained block copolymer solution was applied, on a polyphenylenesulfide film (TORELINA manufactured by TORAY INDUSTRIES, INC.), in afilm thickness of 200 to 250 nm, by a spin coating. The spin coating wasperformed at a spin speed of 500 rpm for 10 seconds, and then performedat a spin speed of 800 rpm for 30 seconds. The thin film applied by thespin coating was left at a room temperature for 10 minutes until thethin film was dried.

Subsequently, the base member was heated for 3 hours in an oven of 170degrees Celsius (first annealing process). It was observed thatconcavities and convexities were formed on the thin film on the surfaceof the heated base member and that micro phase separation of the blockcopolymer was caused. The cross-section of the thin film was observedwith the transmission electron microscope used in Example 1. As shown inthe micrograph of FIG. 12A, which is obtained by the transmissionelectron microscope, PS portions correspond to black portions and PMMAportions correspond to white portions as a result of RuO₄ staining.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetic acid, and was subjectedto cleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the base member was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

The base member was subjected to a heating process (second annealingprocess) for 1 hour in an oven of 140 degrees Celsius so that the thinfilm was subjected to a process for forming a shape of chevrons.

Subsequently, about 10 nm of a thin nickel layer was formed on thesurface of the thin film by a sputtering. Then, the base member wassubjected to an electroforming process under the same condition asExample 1 in a nickel sulfamate bath to precipitate nickel until thethickness of nickel became 250 μm. The base member on which the nickelwas deposited as described above was mechanically peeled off from thenickel electroforming body. The nickel electroforming body from whichthe base member was peeled off was immersed in Chemisol 2303manufactured by The Japan Cee-Bee Chemical Co., Ltd., followed by beingcleaned while being stirred for 2 hours at 50 degrees Celsius.Thereafter, the nickel electroforming body was immersed in atetrahydrofuran solution and an ultrasonic cleaning process was carriedout for 30 minutes. Then, the following process was repeated threetimes. An acrylic-based UV curable resin was applied on the nickelelectroforming body; the applied acrylic-based UV curable resin wascured; and then the cured resin was peeled off. Accordingly, polymercomponent(s) adhered to a part of the surface of the electroforming bodywas(were) removed. FIG. 12B shows a measurement result of thecross-section of the nickel electroforming body using the SEM. It isunderstood from FIG. 12B that concavities and convexities of the nickelelectroforming body were smooth and the cross-section of each convexportion had a chevron shape.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, afluorine-based UV curable resin was applied on a PET substrate(COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). After the nickelmold was pressed against the fluorine-based UV curable resin, thefluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm² and then the nickel mold was peeled off.Accordingly, a diffraction grating made of the UV curable resin film towhich the surface profile of the nickel mold was transferred wasobtained. For the concavity and convexity pattern of the diffractiongrating, the concavity and convexity shape on the surface was analyzedby using the atomic force microscope used in Example 1 to obtain ananalysis image. Analysis conditions of the atomic force microscope werethe same as those in Example 1.

FIG. 12E shows a concavity and convexity analysis image of the surfaceof the resin of the obtained diffraction grating. For comparison, FIG.12C shows a concavity and convexity analysis image of the concavity andconvexity pattern of the block copolymer from which PMMA was selectivelyremoved by the etching process and FIG. 5D shows a concavity andconvexity analysis image of the concavity and convexity pattern of themold formed by the electroforming. The pattern shown in FIG. 12D was apattern transferred from the pattern shown in FIG. 12C, and thus thepattern shown in FIG. 12D was the inverted pattern of the pattern shownin FIG. 12C. It was found out that patterns of FIGS. 12C, 12D, and 12Ehad a common pattern regularity and/or common pattern pitch and that theconcavity and convexity pattern of the block copolymer from which PMMAwas selectively removed by the etching process was satisfactorilyreflected by the electroforming and the transfer to the resin to bethereafter performed.

FIG. 12F shows a concavity and convexity analysis image of thecross-section in the vicinity of the resin surface of the obtaineddiffraction grating. From the analysis images of the concavities andconvexities of the diffraction grating shown in FIGS. 12E and 12F, anaverage height of the concavities and convexities, an average pitch ofthe concavities and convexities, a Fourier-transformed image, an averagevalue and a median of a depth distribution of the concavities andconvexities, and a kurtosis of the concavities and convexities were eachobtained in the same manner as Example 1. The results thereof aredescribed as follows.

Average height: 51 nmAverage pitch: 290 nmAverage value (m) of depth distribution: 45.67 nmMedian (M) of depth distribution: 46.69 nm

Kurtosis: −0.054

FIG. 12G shows a Fourier-transformed image obtained from the analysisimages. As is apparent from the result shown in FIG. 12G, it wasobserved that the Fourier-transformed image showed a circular patternsubstantially centered at an origin at which an absolute value ofwavenumber was 0 μm⁻¹, and that the circular pattern was present withina region where the absolute value of wavenumber was within a range of 10μm⁻¹ or less.

On the UV curable resin film as the diffraction grating obtained asdescribed above, a transparent electrode (ITO, thickness: 120 nm), ahole transporting layer(N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine,thickness: 40 nm), an electron transporting layer (8-hydroxyquinolinealuminum, thickness: 30 nm), a lithium fluoride layer (thickness: 1.5nm), and a metal electrode (aluminum, thickness: 100 nm) were eachstacked by a vapor deposition method to maintain the shape of theconcavities and convexities formed on the surface of the cured resinlayer. Accordingly, the organic EL element was obtained.

Example 9

Toluene was added to 120 mg of the block copolymer 2 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.

Subsequently, 170 mg of methyltrimethoxysilane (MTMS) and 89 mg of1,2-bis(trimethoxysilyl)ethane (BTMSE) were added to 4.75 g ofmethylisobutylketone, followed by being stirred to preparemethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane solution. Thissolution was applied on a glass substrate after cleaning having athickness of 1.1 mm by a spin coating to obtain a glass substrate with acoating film made ofmethyltrimethoxysilane/1,2-bis(trimethoxysilyl)ethane. The spin coatingwas performed at a spin speed of 500 rpm for 10 seconds, and thenperformed at a spin speed of 800 rpm for 30 seconds. The glass substratewith the coating film was sintered for 6 hours in a nitrogen atmosphereat a temperature of 320 degrees Celsius to obtain an organo silicateprocessed glass substrate.

The obtained block copolymer solution was applied, on the organosilicate processed glass substrate, in a film thickness of 200 to 250nm, by a spin coating. The spin coating was performed at a spin speed of500 rpm for 10 seconds, and then performed at a spin speed of 800 rpmfor 30 seconds. After the spin coating, the thin film was left at a roomtemperature for 10 minutes until the thin film was dried.

Subsequently, the base member was heated for 24 hours in an oven of 160degrees Celsius (first annealing process). It was observed thatconcavities and convexities were formed on the thin film on the surfaceof the heated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the substrate was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

The base member was subjected to a heating process (second annealingprocess) for 1 hour in an oven of 125 degrees Celsius so that the thinfilm was subjected to a process for forming a shape of chevrons.

Subsequently, about 10 nm of a thin nickel layer was formed on thesurface of the thin film by a sputtering. Then, the base member wassubjected to an electroforming process under the same condition asExample 1 in a nickel sulfamate bath to precipitate nickel until thethickness of nickel became 250 μm. The base member on which the nickelwas deposited as described above was mechanically peeled off from thenickel electroforming body. The nickel electroforming body from whichthe base member was peeled off was immersed in Chemisol 2303manufactured by The Japan Cee-Bee Chemical Co., Ltd., followed by beingcleaned while being stirred for 2 hours at 50 degrees Celsius.Thereafter, the following process was repeated three times. Anacrylic-based UV curable resin was applied on the nickel electroformingbody; the applied acrylic-based UV curable resin was cured; and then thecured resin was peeled off. Accordingly, polymer component(s) adhered toa part of the surface of the electroforming body was(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, afluorine-based UV curable resin was applied on a PET substrate(COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). After the nickelmold was pressed against the fluorine-based UV curable resin, thefluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm² and then the nickel mold was peeled off.Accordingly, a diffraction grating made of the UV curable resin film towhich the surface profile of the nickel mold was transferred wasobtained. For the concavity and convexity pattern of the diffractiongrating, the concavity and convexity shape on the surface was analyzedby using the atomic force microscope used in Example 1 to obtain ananalysis image. Analysis conditions of the atomic force microscope werethe same as those in Example 1.

FIG. 13D shows the obtained concavity and convexity analysis image. Forcomparison, FIG. 13A shows a concavity and convexity analysis image ofthe concavity and convexity pattern of the block copolymer from whichPMMA was selectively removed by the etching process; FIG. 13B shows aconcavity and convexity analysis image of the concavity and convexitypattern for which the process for forming the shape of chevrons wasperformed in the second anneal step after the etching process; and FIG.13C shows a concavity and convexity analysis image of the concavity andconvexity pattern of the mold formed by the electroforming. The patternshown in FIG. 13C was a pattern transferred from the pattern shown inFIG. 13A, and thus the pattern shown in FIG. 13C was the invertedpattern of those shown in FIGS. 13A, 13B, and 13D. It was found out thatpatterns of FIGS. 13A, 13B, 13C, and 13D had a common pattern regularityand/or common pattern pitch and that the planar shape of the concavityand convexity pattern of the block copolymer from which PMMA wasselectively removed by the etching process was satisfactorily reflectedby the second annealing process, the electroforming, and the transfer tothe resin to be thereafter performed.

FIG. 13E shows a concavity and convexity analysis image of thecross-section in the vicinity of the surface of the obtained diffractiongrating. From the concavity and convexity analysis images (FIGS. 13D and13E) of the surfaces of the diffraction grating, an average height ofthe concavities and convexities, an average pitch of the concavities andconvexities, an average value (m) and a median (M) of a depthdistribution of the concavities and convexities, and a kurtosis of theconcavities and convexities of the diffraction grating were eachobtained in the same manner as Example 1. The results thereof aredescribed as follows.

Average height: 110 nmAverage pitch: 290 nmAverage value (m) of depth distribution: 91.22 nmMedian (M) of depth distribution: 95.9 nm

Kurtosis: −0.348

FIG. 13F shows a Fourier-transformed image obtained from the analysisimages. As is apparent from the result shown in FIG. 13F, it wasobserved that the Fourier-transformed image showed a circular patternsubstantially centered at an origin at which an absolute value ofwavenumber was 0 μm⁻¹, and that the circular pattern was present withina region where the absolute value of wavenumber was within a range of 10μm⁻¹ or less.

On the UV curable resin film as the diffraction grating obtained asdescribed above, a transparent electrode (ITO, thickness: 120 nm), ahole transporting layer(N,N-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine,thickness: 40 nm), an electron transporting layer (8-hydroxyquinolinealuminum, thickness: 30 nm), a lithium fluoride layer (thickness: 1.5nm), and a metal electrode (aluminum, thickness: 100 nm) were eachstacked by a vapor deposition method to maintain the shape of theconcavities and convexities formed on the surface of the cured resinlayer. Accordingly, the organic EL element was obtained.

Comparative Example 1

A nickel electroforming body was obtained in the similar manner asExample 1, except that the heating process (second annealing process)for 1 hour in the oven of 140 degrees Celsius was not performed. FIG.14A shows a SEM measurement result of the cross-section of the nickelelectroforming body. The concavity and convexity shape on the surface ofthe nickel electroforming body was measured by using the atomic forcemicroscope used in Example 1 to obtain an analysis image. Analysisconditions of the atomic force microscope were the same as those inExample 1. The obtained analysis image is shown in FIG. 14C. Forcomparison, FIG. 14B shows a concavity and convexity analysis image ofthe concavity and convexity pattern of the block copolymer from whichPMMA was selectively removed by the etching process.

As is clear from FIG. 14A, regarding the nickel electroforming bodyobtained in this example, the concavities and convexities on the surfacewere ununiform and coarse as compared with those obtained in Example 1,and further portions like overhangs were observed. Furthermore, it wasfound that polystyrene (portions look black) was remained at eachconcave portion of the nickel surface. In FIG. 14C, the periodicconcavity and convexity pattern which appeared in FIG. 14B was notobserved. Therefore, it is considered that the concavity and convexitypattern of the block copolymer from which PMMA was selectively removedby the etching process had a cross-section structure (see FIG. 1C) whichwas not suitable for the transfer even by the electroforming.

Comparative Example 2

A nickel electroforming body was obtained in the similar manner asExample 8, except that the heating process (second annealing process)for 1 hour in the oven of 140 degrees Celsius was not performed. FIG.15A shows a SEM measurement result of the cross-section of the nickelelectroforming body. The concavity and convexity shape of the nickelelectroforming body was measured by using the atomic force microscopeused in Example 1 to obtain an analysis image. Analysis conditions ofthe atomic force microscope were the same as those in Example 1. Theobtained analysis image is shown in FIG. 15C. For comparison, FIG. 15Bshows a concavity and convexity analysis image of the concavity andconvexity pattern of the block copolymer from which PMMA was selectivelyremoved by the etching process.

As is clear from FIG. 15A, regarding the nickel electroforming bodyobtained in this example, the concavities and convexities on the surfacewere ununiform and coarse as compared with those obtained in Example 8,and further portions like overhangs were observed. Furthermore, it wasfound that polystyrene (portions look black) was remained at eachconcave portion of the nickel. In FIG. 15C, the periodic concavity andconvexity pattern which appeared in FIG. 15B was not observed.Therefore, it is considered that the concavity and convexity pattern ofthe block copolymer from which PMMA was selectively removed by theetching process had a cross-section structure which was not suitable forthe transfer by the electroforming.

Comparative Example 3

Toluene was added to 120 mg of the block copolymer 1 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.

Subsequently, 0.7 g of octadecyldimethylchlorosilane (ODS) was added to500 ml of heptane, followed by being stirred to prepare 2.0 mM of ODSsolution. A glass substrate after cleaning having a thickness of 1.1 mmwas immersed in the solution and stationarily placed for 24 hours. Thisprocessed substrate was subjected to ultrasonic cleaning with chloroformfor 10 minutes and then subjected to ultrasonic cleaning with pure waterfor 10 minutes, followed by being dried. Accordingly, an ODS-processedglass substrate was obtained.

The obtained block copolymer solution was applied, on the ODS-processedglass substrate, in a film thickness of 200 to 250 nm, by a spincoating. The spin coating was performed at a spin speed of 500 rpm for10 seconds, and then performed at a spin speed of 800 rpm for 30seconds. After the spin coating, the thin film was left at a roomtemperature for 10 minutes until the thin film was dried.

Subsequently, the base member was heated for 3 hours in an oven of 160degrees Celsius (annealing process). It was observed that concavitiesand convexities were formed on the thin film on the surface of theheated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the base member was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

Subsequently, about 10 nm of a thin nickel layer was formed on thesurface of the thin film by a sputtering. Then, the base member wassubjected to an electroforming process under the same condition asExample 1 in a nickel sulfamate bath to precipitate nickel until thethickness of nickel became 250 μm. The base member on which the nickelwas deposited as described above was mechanically peeled off from thenickel electroforming body. The nickel electroforming body from whichthe base member was peeled off was immersed in Chemisol 2303manufactured by The Japan Cee-Bee Chemical Co., Ltd., followed by beingcleaned while being stirred for 2 hours at 50 degrees Celsius.Thereafter, the nickel electroforming body was immersed in atetrahydrofuran solution and an ultrasonic cleaning process was carriedout for 30 minutes.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Then, a fluorine-based UVcurable resin was applied on a PET substrate (COSMOSHINE A-4100manufactured by Toyobo Co., Ltd.). After the nickel mold was pressedagainst the fluorine-based UV curable resin, the fluorine-based UVcurable resin was cured by irradiation with ultraviolet rays at 600mJ/cm² and then the nickel mold was peeled off. Accordingly, adiffraction grating made of the UV curable resin film to which thesurface profile of the nickel mold was transferred was obtained. For theconcavity and convexity pattern of the diffraction grating, theconcavity and convexity shape on the surface was analyzed by using theatomic force microscope used in Example 1 to obtain an analysis image.However, the shape representing the concavity and convexity on thesurface was not observed in the analysis image. For reference, theanalysis image of the concavity and convexity pattern of the blockcopolymer from which PMMA was selectively removed by the etching processand the analysis image of concavity and convexity pattern of the surfaceof the nickel electroforming body were each obtained by performingmeasurement using the atomic force microscope used in Example 1.Analysis conditions of the atomic force microscope were the same asthose in Example 1. Respective analysis images are shown in FIGS. 16Aand 16B.

It was found out that the periodic concavity and convexity pattern whichappeared in FIG. 16A did not appear at all in FIG. 16B. Therefore, it isconsidered that the concavity and convexity pattern of the blockcopolymer from which PMMA was selectively removed by the etching processhad a cross-section structure which was not suitable for the transfer bythe electroforming.

Comparative Example 4

Toluene was added to 120 mg of the block copolymer 1 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.The obtained block copolymer solution was applied, on a polyphenylenesulfide film (TORELINA manufactured by TORAY INDUSTRIES, INC.), in afilm thickness of 200 to 250 nm, by a spin coating. The spin coating wasperformed at a spin speed of 500 rpm for 10 seconds, and then performedat a spin speed of 800 rpm for 30 seconds. The thin film applied by thespin coating was left at a room temperature for 10 minutes until thethin film was dried.

Subsequently, the base member was heated for 5 hours in an oven of 170degrees Celsius (first annealing process). It was observed thatconcavities and convexities were formed on the thin film on the surfaceof the heated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetic acid, and was subjectedto cleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the base member was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

Subsequently, about 10 nm of a thin nickel layer was formed on thesurface of the thin film by a sputtering without performing the secondannealing process. Then, the base member was subjected to anelectroforming process under the same condition as Example 1 in a nickelsulfamate bath to precipitate nickel until the thickness of nickelbecame 250 μm. The base member on which the nickel was deposited asdescribed above was mechanically peeled off from the nickelelectroforming body. The nickel electroforming body from which the basemember was peeled off was immersed in Chemisol 2303 manufactured by TheJapan Cee-Bee Chemical Co., Ltd., followed by being cleaned while beingstirred for 2 hours at 50 degrees Celsius. Thereafter, the nickelelectroforming body was immersed in a tetrahydrofuran solution and anultrasonic cleaning process was carried out for 30 minutes.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, afluorine-based UV curable resin was applied on a PET substrate(COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). The fluorine-basedUV curable resin was cured by irradiation with ultraviolet rays at 600mJ/cm² while the nickel mold was pressed against the fluorine-based UVcurable resin. Then, the nickel mold was peeled off from the curedresin. Accordingly, a diffraction grating made of the UV curable resinfilm to which the surface profile of the nickel mold was transferred wasobtained. For the concavity and convexity pattern of the diffractiongrating, the concavity and convexity shape on the surface was analyzedby using the atomic force microscope used in Example 1. However, theshape representing the concavity and convexity on the surface was notobserved in the analysis image. For reference, the analysis image of theconcavity and convexity pattern of the block copolymer from which PMMAwas selectively removed by the etching process and the analysis image ofthe concavity and convexity pattern on the surface of the nickelelectroforming body were each obtained by performing measurement usingthe atomic force microscope used in Example 1. Analysis conditions ofthe atomic force microscope were the same as those in Example 1.Respective analysis images are shown in FIGS. 17A and 17B.

It was found out that the periodic concavity and convexity pattern whichappeared in FIG. 17A did not appear in FIG. 17B. Therefore, it isconsidered that the concavity and convexity pattern of the blockcopolymer from which PMMA was selectively removed by the etching processhad a cross-section structure which was not suitable for the transfer bythe electroforming.

Comparative Example 5

Toluene was added to 120 mg of the block copolymer 5 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.

Subsequently, 0.7 g of octadecyl trichlorosilane (OTS) was added to 500ml of heptane, followed by being stirred to prepare 2.0 mM of OTSsolution. A glass substrate after cleaning having a thickness of 1.1 mmwas immersed in the solution and stationarily placed for 24 hours. Thisprocessed substrate was subjected to ultrasonic cleaning with chloroformfor 10 minutes and then subjected to ultrasonic cleaning with pure waterfor 10 minutes, followed by being dried. Accordingly, an OTS-processedglass substrate was obtained.

The obtained block copolymer solution was applied, on the OTS-processedglass substrate, in a film thickness of 200 to 250 nm, by a spincoating. The spin coating was performed at a spin speed of 500 rpm for10 seconds, and then performed at a spin speed of 800 rpm for 30seconds. After the spin coating, the thin film was left at a roomtemperature for 10 minutes until the thin film was dried.

Subsequently, the base member was heated for 8 hours in an oven of 190degrees Celsius (first annealing process). It was observed thatconcavities and convexities were formed on the thin film on the surfaceof the heated base member and that micro phase separation of the blockcopolymer was caused.

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the base member was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

Subsequently, about 30 nm of a thin nickel layer was formed on thesurface of the thin film by a vapor deposition method without performingthe second annealing process. Then, the base member was subjected to anelectroforming process under the same condition as Example 1 in a nickelsulfamate bath to precipitate nickel until the thickness of nickelbecame 250 μm. The base member on which the nickel was deposited asdescribed above was mechanically peeled off from the nickelelectroforming body. Then, the following process was repeated threetimes. An acrylic-based UV curable resin was applied on the nickelelectroforming body from which the base member was peeled off; theapplied acrylic-based UV curable resin was cured; and then the curedresin was peeled off. Further, the nickel electroforming body wasimmersed in Chemisol 2303 manufactured by The Japan Cee-Bee ChemicalCo., Ltd., followed by being cleaned while being stirred for 2 hours at50 degrees Celsius. Accordingly, polymer component(s), adhered to a partof the surface of the electroforming body, which was(were) visuallyconfirmed was(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, afluorine-based UV curable resin was applied on a PET substrate(COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). After the nickelmold was pressed against the fluorine-based UV curable resin, thefluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm² and then the nickel mold was peeled off.Accordingly, a diffraction grating made of the UV curable resin film towhich the surface profile of the nickel mold was transferred wasobtained.

For the concavity and convexity pattern of the surface of the nickelelectroforming body, the analysis image was obtained by performingmeasurement using the atomic force microscope used in Example 1.Analysis conditions of the atomic force microscope were the same asthose in Example 1. The analysis image is shown in FIG. 18. Although thesecond annealing process was not performed in this example, it was foundout from FIG. 18 that the periodic concavity and convexity patternappeared on the surface of the diffraction grating while it was unclear(the pattern was not as clear as that of Example 1). The reason thereofis considered that the molecular weight of the block copolymer 5 wasrelatively low.

Comparative Example 6

Toluene was added to 120 mg of the block copolymer 2 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.The obtained block copolymer solution was applied, on a polyphenylenesulfide film (TORELINA manufactured by TORAY INDUSTRIES, INC.), in afilm thickness of 200 to 250 nm, by a spin coating to form a thin film.The spin coating was performed at a spin speed of 500 rpm for 10seconds, and then performed at a spin speed of 800 rpm for 30 seconds.The thin film applied by the spin coating was left at a room temperaturefor 10 minutes until the thin film was dried.

Subsequently, the base member was heated for 5 hours in an oven of 170degrees Celsius (first annealing process).

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetic acid, and was subjectedto cleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the base member was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

Subsequently, about 30 nm of a thin nickel layer was formed on thesurface of the thin film by a vapor deposition method. Then, the basemember was subjected to an electroforming process under the samecondition as Example 1 in a nickel sulfamate bath to precipitate nickeluntil the thickness of nickel became 250 μm. The base member on whichthe nickel was deposited as described above was mechanically peeled offfrom the nickel electroforming body. Then, the following process wasrepeated three times. An acrylic-based UV curable resin was applied onthe nickel electroforming body from which the base member was peeledoff; the applied acrylic-based UV curable resin was cured; and then thecured resin was peeled off. Further, the nickel electroforming body wasimmersed in Chemisol 2303 manufactured by The Japan Cee-Bee ChemicalCo., Ltd., followed by being cleaned while being stirred for 2 hours at50 degrees Celsius. Accordingly, polymer component(s), adhered to a partof the surface of the electroforming body, which was(were) visuallyconfirmed was(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained.

Subsequently, a fluorine-based UV curable resin was applied on a PETsubstrate (COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). Afterthe nickel electroforming body was pressed against the fluorine-based UVcurable resin, the fluorine-based UV curable resin was cured byirradiation with ultraviolet rays at 600 mJ/cm² and then the nickel moldwas peeled off. Accordingly, a diffraction grating made of the UVcurable resin film to which the surface profile of the nickel mold wastransferred was obtained. For the concavity and convexity pattern of thediffraction grating, the concavity and convexity shape on the surfacewas measured by using the atomic force microscope used in Example 1.However, the concavity and convexity shape on the surface was notobserved. For reference, the analysis image of the concavity andconvexity pattern of the surface of the nickel electroforming body wasobtained by performing measurement using the atomic force microscopeused in Example 1. Analysis conditions of the atomic force microscopewere the same as those in Example 1. The obtained analysis image isshown in FIG. 19. It was found out that the periodic concavity andconvexity pattern did not appear at all in FIG. 19.

Comparative Example 7

Toluene was added to 120 mg of the block copolymer 1 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.The obtained block copolymer solution was applied, on a polyphenylenesulfide film (TORELINA manufactured by TORAY INDUSTRIES, INC.), in afilm thickness of 200 to 250 nm, by a spin coating. The spin coating wasperformed at a spin speed of 500 rpm for 10 seconds, and then performedat a spin speed of 800 rpm for 30 seconds. The thin film applied by thespin coating was left at a room temperature for 10 minutes until thethin film was dried.

Subsequently, the base member was heated for 6 hours in an oven of 160degrees Celsius (first annealing process).

The heated thin film was subjected to an etching process as describedbelow. The thin film was irradiated with ultraviolet rays at anirradiation intensity of 30 J/cm² by use of a high pressure mercurylamp. Then, the thin film was immersed in acetic acid, and was subjectedto cleaning with ion-exchanged water, followed by being dried. Byperforming the etching process, PMMA on the base member was selectivelyremoved to obtain a thin film with a minute concavity and convexitypattern.

Subsequently, about 30 nm of a thin nickel layer was formed on thesurface of the thin film by a vapor deposition method. Then, the basemember was subjected to an electroforming process under the samecondition as Example 1 in a nickel sulfamate bath to precipitate nickeluntil the thickness of nickel became 250 μm. The base member on whichthe nickel was deposited as described above was mechanically peeled offfrom the nickel electroforming body. Then, the following process wasrepeated three times. An acrylic-based UV curable resin was applied onthe nickel electroforming body from which the base member was peeledoff; the applied acrylic-based UV curable resin was cured; and then thecured resin was peeled off. Further, the nickel electroforming body wasimmersed in Chemisol 2303 manufactured by The Japan Cee-Bee ChemicalCo., Ltd., followed by being cleaned while being stirred for 2 hours at50 degrees Celsius. Accordingly, polymer component(s), adhered to a partof the surface of the electroforming body, which was(were) visuallyconfirmed was(were) removed.

Subsequently, the nickel electroforming body was immersed in HD-2101THmanufactured by Daikin Chemicals Sales, Co., Ltd. for about 1 minute andwas dried, and then stationarily placed overnight. The next day, thenickel electroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained. Subsequently, afluorine-based UV curable resin was applied on a PET substrate(COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). After the nickelmold was pressed against the fluorine-based UV curable resin, thefluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm² and then the nickel mold was peeled off.Accordingly, a diffraction grating made of the UV curable resin film towhich the surface profile of the nickel mold was transferred wasobtained. For the concavity and convexity pattern of the diffractiongrating, the concavity and convexity shape on the surface was measuredby using the atomic force microscope used in Example 1. However, theconcavity and convexity shape on the surface was not observed. Forreference, the analysis image of the concavity and convexity pattern ofthe surface of the nickel electroforming body was obtained by performingmeasurement using the atomic force microscope used in Example 1.Analysis conditions of the atomic force microscope were the same asthose in Example 1. The obtained analysis image is shown in FIG. 20. Itwas found out that the periodic concavity and convexity pattern did notappear at all in FIG. 20.

Comparative Example 8

Toluene was added to 120 mg of the block copolymer 2 and 30 mg ofPolyethylene Glycol 4000 manufactured by Tokyo Chemical Industry Co.,Ltd. so that the total amount thereof was 10 g, followed by dissolvingthem. Then, it was filtrated or filtered through a membrane filterhaving a pore diameter of 0.5 μm to obtain a block copolymer solution.Subsequently, 170 mg of methyltrimethoxysilane (MTMS) and 89 mg of1,2-bis(trimethoxysilyl)ethane (BTMSE) were added to 4.75 g ofmethylisobutylketone, followed by being stirred to preparemethylisobutylketone/1,2-bis(trimethoxysilyl)ethane solution. Thissolution was applied on a glass substrate after cleaning having athickness of 1.1 mm by a spin coating to obtain a glass substrate with acoating film made ofmethylisobutylketone/1,2-bis(trimethoxysilyl)ethane. The spin coatingwas performed at a spin speed of 500 rpm for 10 seconds, and thenperformed at a spin speed of 800 rpm for 30 seconds.

The glass substrate with the coating film was sintered for 6 hours in anitrogen atmosphere at a temperature of 280 degrees Celsius to obtain anorgano silicate processed glass substrate. The prepared block copolymersolution was applied on the organo silicate processed glass substrate bya spin coating to form a thin film. The spin coating was performed at aspin speed of 500 rpm for 10 seconds, and then performed at a spin speedof 800 rpm for 30 seconds. After the spin coating, the thin film wasleft at a room temperature for 10 minutes.

Subsequently, the glass substrate with the thin film was subjected to anannealing process for 5 hours in an oven of 160 degrees Celsius (firstannealing process). In order to selectively remove PMMA from theobtained thin film by an etching, the glass substrate with the thin filmwas irradiated with ultraviolet rays at an irradiation intensity of 30J/cm² by use of a high pressure mercury lamp. Then, the glass substratewith the thin film was immersed in acetone, and was subjected tocleaning with ion-exchanged water, followed by being dried. By removingPMMA as described above, a concavity and convexity thin film which wassubstantially made of PS was obtained.

The glass substrate with the thin film was subjected to a heatingprocess for 80 hours in an oven of 95 degrees Celsius which was lowerthan the glass transition temperature of PS. After the heating process,about 10 nm of a thin nickel layer was formed on the surface of theconcavity and convexity thin film by a sputtering. Then, the substratewas subjected to an electroforming process under the same condition asExample 1 in a nickel sulfamate bath to precipitate nickel until thethickness of nickel became 250 μm. The glass substrate with the thinfilm was mechanically peeled off from the obtained nickel electroformingbody. The surface of the nickel electroforming body from which thesubstrate was peeled off was immersed in Chemisol 2303 manufactured byThe Japan Cee-Bee Chemical Co., Ltd., followed by being cleaned whilebeing stirred for 2 hours at 50 degrees Celsius. Thereafter, transferwas performed three times using an acrylic-based UV curable resin. Thenickel electroforming body was immersed in HD-2101TH manufactured byDaikin Chemicals Sales, Co., Ltd. for about 1 minute and was dried, andthen stationarily placed overnight. The next day, the nickelelectroforming body was immersed in HDTH manufactured by DaikinChemicals Sales, Co., Ltd. to perform an ultrasonic cleaning process forabout 1 minute. Accordingly, a nickel mold for which a mold-releasetreatment had been performed was obtained.

Subsequently, a fluorine-based UV curable resin was applied on a PETsubstrate (COSMOSHINE A-4100 manufactured by Toyobo Co., Ltd.). Then,the fluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm² while pressing the nickel mold againstthe fluorine-based UV curable resin. Accordingly, a PET substrate withthe resin to which the surface profile of the nickel mold wastransferred was obtained. For the PET substrate with the resin obtainedas described above, the concavity and convexity shape on the resinsurface was analyzed by using the atomic force microscope used inExample 1. However, the shape representing the concavity and convexityon the surface was not observed in the analysis image. For reference,the analysis image of the concavity and convexity pattern of the blockcopolymer from which PMMA was selectively removed by the etching processand the analysis image of the concavity and convexity pattern of thesurface of the nickel electroforming body were each obtained byperforming measurement using the atomic force microscope used inExample 1. Analysis conditions of the atomic force microscope were thesame as those in Example 1. Respective analysis images are shown inFIGS. 21A and 21B.

It was found out that the periodic concavity and convexity pattern whichappeared in FIG. 21A did not appear at all in FIG. 21B. Therefore, it isconsidered that the concavity and convexity pattern of the blockcopolymer from which PMMA was selectively removed by the etching processhad a cross-section structure which was not suitable for the transfer bythe electroforming.

From the results of Examples 1 to 9 and Comparative Examples 1 to 4 and6 to 8 as described above, it is found out that the concavity andconvexity pattern of the thin film in which the micro phase separationwas caused was not satisfactorily transferred to the nickel layer, in acase that the nickel layer was deposited by the electroforming withoutthe second annealing process of the thin film for which the etchingprocess was performed. In Comparative Example 5, since the molecularweight of the block copolymer was relatively low (not more than500,000), the concavity and convexity pattern was transferred to thenickel electroforming body without the second annealing process.However, as understood from Comparative Examples 6 and 7, in a case thatthe molecular weight of the block copolymer exceeded 500,000, theconcavity and convexity pattern could not be transferred to the nickelelectroforming body at all without the second annealing process.Therefore, it is found out that, regardless of the molecular weight ofthe block copolymer, the second annealing process is required to obtaina mold having a desired minute pattern. In particular, in a case that adevice such as the diffraction grating to be produced by the mold isused in a wide visible region, a pitch such that diffraction isgenerated in such a wavelength region is required. Thus, the molecularweight of the block copolymer in which the micro phase separation iscaused desirably exceeds 500,000.

As understood from the results of the current efficiency and the powerefficiency in Examples 2 and 4, the organic EL element of the presentinvention has superior light-extraction efficiency. Further, as isapparent from the measurement results of directivity of light emissionof the organic EL element in these Examples, the directivity of lightemission of the organic EL element of the present invention issufficiently low.

In the above Example(s), the diffraction grating, of which the averageheight of the concavities and convexities was within a range from 40 to110 nm, and the average pitch was within a range from 110 to 480 nm, wasobtained. It was confirmed that the satisfactory diffraction wasgenerated, provided that the average height and the average pitch of theconcavities and convexities of the diffraction grating were at leastwithin the above ranges. Further, in the above Example(s), thediffraction grating, of which the kurtosis of the concavities andconvexities was within a range from −1.2 to 0.729, was obtained. It wasfound out that, if the kurtosis was at least within the above range, thesatisfactory diffracted light was generated and no leak current wasgenerated. Regarding the cross-section shape of the concavity andconvexity structure formed in the diffraction grating obtained in theabove Example(s), it was found that the average value m and the median Mof the depth distribution of the concavities and convexities on thecross-section satisfied the following empiric formula:

(1.062m−2.2533)×0.95≦M≦(1.062m−2.2533)×1.05

Example 10

In this example, a nickel mold (nickel substrate), for which amold-release treatment was performed, was obtained by using a BCP methodsimilar to Example 1. Subsequently, a fluorine-based UV curable resinwas applied on a PET substrate (easily-adhesion PET film manufactured byToyobo Co., Ltd., product name: COSMOSHINE A-4100). Then, thefluorine-based UV curable resin was cured by irradiation withultraviolet rays at 600 mJ/cm², with the nickel mold being pressedthereto. After curing of the resin, the nickel mold was peeled off fromthe cured resin. Accordingly, a diffraction grating mold made of the PETsubstrate with the resin film to which the surface profile of the nickelmold was transferred was obtained. 2.5 g of tetraethoxysilane (TEOS) and2.1 g of methyltriethoxysilane (MTES) were added by drops to a mixtureof 24.3 g of ethanol, 2.16 g of water, and 0.0094 g of concentratedhydrochloric acid, followed by being stirred for 2 hours at atemperature of 23 degrees Celsius and humidity of 45% to obtain a solsolution. The sol solution was applied on a soda-lime glass plate of15×15×0.11 cm by a bar coating. Doctor Blade (manufactured by YoshimitsuSeiki Co., Ltd.) was used as a bar coater. The doctor blade was designedso that the film thickness of the coating film was 5 However, the doctorblade was adjusted so that the film thickness of the coating film was 40by sticking an imide tape having the thickness of 35 μm to the doctorblade. When 60 seconds have elapsed after the application of the solsolution, the diffraction grating mold, made of the PET substrate withthe resin film to which the surface profile of the nickel mold wastransferred, which was prepared similar to Example 1, was pressedagainst the coating film on the glass plate by a pressing roll using amethod described below.

At first, the surface on which the pattern of the mold has been formedwas pressed against the coating film on the glass substrate whilerotating the pressing roll of which temperature was 23 degrees Celsiusfrom one end to the other end of the glass substrate. Immediately aftercompletion of the pressing, the substrate was moved on a hot plate andthen heated at a temperature of 100 degrees Celsius (pre-sintering).After continuing the heating for 5 minutes, the substrate was removedfrom the hot plate and the mold was manually peeled off from thesubstrate from the edge. The mold was peeled off such that an angle(peel angle) of the mold with respect to the substrate was about 30°.

Subsequently, a main sintering was performed by heating the substratefor 60 minutes in an oven of 300 degrees Celsius, and then the patterntransferred to the coating film was evaluated.

For the diffraction grating, the analysis image of the concavity andconvexity shape on the resin surface was obtained by using the atomicforce microscope used in Example 1. Analysis conditions of the atomicforce microscope were the same as those in Example 1.

<Average Height of Concavities and Convexities>

A concavity and convexity analysis image was obtained as described aboveby performing a measurement in a randomly selected measuring region of 3μm square (length: 3 μm, width: 3 μm) in the diffraction grating.Distances between randomly selected concave portions and convex portionsin the depth direction were measured at 100 points or more in theconcavity and convexity analysis image, and the average of the distanceswas calculated as the average height (depth) of the concavities andconvexities. The average height of the concavity and convexity patternobtained by the analysis image in this example was 56 nm.

<Fourier-Transformed Image>

A concavity and convexity analysis image was obtained by performing ameasurement in a randomly selected measuring region of 3 μm square(length: 3 μm, width: 3 μm) in the diffraction grating similar toExample 1. It was confirmed that the Fourier-transformed image showed acircular pattern substantially centered at an origin at which anabsolute value of wavenumber was 0 μm⁻¹, and that the circular patternwas present within a region where the absolute value of wavenumber waswithin a range of 10 μm⁻¹ or less.

As a result of the image analysis of the obtained Fourier-transformedimage, the wavenumber 2.38 μm⁻¹ was the most intensive. That is, theaverage pitch was 420 nm. The average pitch could be obtained asfollows. For each of the points of Fourier-transformed image, intensityand distance (unit: μm⁻¹) from the origin of Fourier-transformed imagewere obtained. Then, the average value of the intensity was obtained forthe points each having the same distance from the origin. As describedabove, a relation between the distance from the origin of theFourier-transformed image and the average value of the intensity wasplotted, a fitting with a spline function was carried out, and thewavenumber of peak intensity was regarded as the average wavenumber(μm⁻¹). For the average pitch, it is allowable to make a calculation byanother method, for example, a method for obtaining the average pitch ofthe concavities and convexities as follows. That is, a concavity andconvexity analysis image is obtained by performing a measurement in arandomly selected measuring region of 3 μm square (length: 3 μm, width:3 μm) in the diffraction grating, then the distances between randomlyselected adjacent convex portions or between randomly selected adjacentconcave portions are measured at 100 points or more in the concavity andconvexity analysis image, and then an average of these distances isdetermined.

<Manufacture of Organic EL Element>

A glass substrate with a pattern made of a sol-gel material layer as thediffraction grating obtained as described above was cleaned with a brushto remove foreign matter and the like adhered thereto, then organicmatter and the like was removed by an alkaline cleaner and an organicsolvent. On the substrate cleaned as described above, a film of ITOhaving the thickness of 120 nm was formed at a temperature of 300degrees Celsius by a sputtering method. A photoresist was applied and anexposure was performed with an electrode mask pattern, and then anetching was performed by a developer. Accordingly, a transparentelectrode having a predetermined pattern was obtained. The obtainedtransparent electrode was cleaned with a brush, and organic matter andthe like was removed by an alkaline cleaner and an organic solvent.Then, transparent electrode was subjected to a UV-ozone process. On thetransparent electrode processed as described above, a hole transportinglayer (4,4′,4″ tris(9-carbazole)triphenylamine, thickness: 35 nm), alight emitting layer (tris(2-phenylpyridinato)iridium(III) complex-doped4,4′,4″tris(9-carbazole)triphenylamine, thickness: 15 nm;tris(2-phenylpyridinato)iridium(III) complex-doped1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene, thickness: 15 nm), anelectron transporting layer(1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene, thickness: 65 nm), and alithium fluoride layer (thickness: 1.5 nm) were each stacked by a vapordeposition method, and further a metal electrode (aluminum, thickness:50 nm) was formed by the vapor deposition method. Accordingly, as shownin FIG. 22, the organic EL element 200, which has a coating film(sol-gel material layer) 42, a transparent electrode 92, an organiclayer 94 (a hole transporting layer 95, a light-emitting layer 96, andan electron transporting layer 97), and a metal electrode 98 on asubstrate 40 in this order, was obtained.

In the process as described above, the substrate was formed of thesol-gel material and had the superior mechanical strength. Thus, evenwhen the cleaning with the brush was performed for the substrate and thesurface of the concavity and convexity pattern after formation of thetransparent electrode as described above, damage, adhesion of theforeign matter, projection on the transparent electrode and the likewere less likely to occur, and thereby element failure therefrom couldbe suppressed. Therefore, the obtained organic EL element was superior,as compared with a case in which a curable resin substrate was used, interms of the mechanical strength of the substrate having the concavityand convexity pattern. Further, the substrate made of the sol-gelmaterial produced in accordance with the method of this example hadsatisfactory chemical resistance, and had alkali resistance superior tothe substrate formed of a curable resin material. Therefore, thesubstrate of this example had a certain corrosion resistance to alkalinefluid and the organic solvent used for the cleaning step of thesubstrate and the transparent electrode, and thus it is possible to usevarious cleaning liquids. Further, an alkaline developer is used at thetime of the patterning of the transparent substrate in some cases. Thesubstrate in this example also has the corrosion resistance to such adeveloper. In this respect, the substrate in this example has anadvantage over the curable resin substrate having generally lowresistance in the alkaline fluid. Further, the substrate formed of thesol-gel material has superior UV resistance and superior weatherresistance as compared with the curable resin substrate. Therefore, thesubstrate in this example also has resistance to a UV-ozone cleaningprocess after the formation of the transparent electrode. Further, in acase that the organic EL element produced by the method of this exampleis used outside or outdoors, it is possible to suppress deteriorationdue to sunlight as compared with the case in which the curable resinsubstrate is used.

<Evaluation of Light Emission Efficiency of Organic EL Element>

A light emission efficiency of the organic EL element obtained in thisexample was measured by the following method. That is, a voltage wasapplied to the obtained organic EL element, and then the applied voltageV and a current I flowing through the organic EL element were measuredwith a source measurement instrument (manufactured by ADC CORPORATION,R6244), and a total luminous flux amount L was measured with a totalflux measurement apparatus manufactured by Spectra Co-op. From the thusobtained measured value of the applied voltage V, the current I, and thetotal luminous flux amount L, a luminance value L′ was calculated. Here,for the current efficiency, the following calculation formula (F1) wasused:

Current efficiency=(L′/I)×S  (F1)

and, for the power efficiency, the following calculation formula (F2)was used:

Power efficiency=(L′/I/V)×S  (F2)

Accordingly, the current efficiency and the power efficiency of theorganic EL element were calculated. In the above formulae, S is alight-emitting or luminescent area of the element. Noted that the valueof the luminance L′ was calculated on the assumption that lightdistribution characteristic of the organic EL element followed Lambert'slaw, and the following calculation formula (F3) was used:

L′=L/π/S  (F3)

The current efficiency of the organic EL element of this example at aluminance of 1000 cd/m² was about 1.4 times that of the organic ELelement having no concavity and convexity on the glass substrate.Further, the current efficiency of the organic EL element of thisexample at the luminance of 1000 cd/m² was about 1.6 times that of theorganic EL element having no concavity and convexity on the glasssubstrate. Therefore, the organic EL element of the present inventionhad a sufficient external extraction efficiency.

<Evaluation of Light Emission Directivity of Organic EL Element>

The directivity of light emission of the organic EL element obtained inthis example was evaluated by the following method. That is, the organicEL element in a luminescent state was visually observed in all thedirections (directions of all around) 360°. Neither particularly brightsites nor particularly dark sites were observed when the organic ELelement obtained in Example 3 was observed in any of the directions ofall around 360°, and the brightness was uniform in all the directions.In this way, it was shown that the directivity of light emission of theorganic EL element of the present invention was sufficiently low.

As described above, a temperature at the time of forming the film of thetransparent electrode (ITO) of the organic EL element in this examplewas 300 degrees Celsius. It is allowable that the temperature at thetime of forming the film of the transparent electrode is lower than 300degrees Celsius, but the transparent electrode is desired to have lowresistivity and the film formation is preferably performed at a hightemperature to increase crystallinity. In a case that the temperatureduring the film formation is low (about 100 degrees Celsius), an ITOfilm formed on the substrate is relatively amorphous, has inferiorspecific resistance, has inferior adhesion property between thesubstrate and the ITO thin film. Although the concavity and convexitypattern formed of a general UV curable resin and the like had difficultyin withstanding a film formation step at a high temperature, theconcavity and convexity pattern can be applied even in the filmformation step at the high temperature by using the sol-gel materialwhich is an example of ceramic. Therefore, the method in this example isalso suitable for producing the substrate (diffraction grating) for theorganic EL element.

According to the present invention, it is possible to produce a mold fornanoimprint, which is suitable for manufacturing a diffraction gratingused for a device such as an organic EL element and has excellent massproducibility, easily and with high accuracy. The diffraction gratingobtained by using this mold and the organic EL in which the diffractinggrating is used have low light directivity and superior light-extractionefficiency.

What is claimed is:
 1. A mold for minute pattern transfer produced by aproducing method, the producing method comprising a step of applying ablock copolymer solution made of at least a first polymer and a secondpolymer on a surface of a base member; a step of drying a coating filmon the base member; a first heating step for heating the coating filmafter the drying at a temperature higher than a glass transitiontemperature of a block copolymer of the block copolymer solution; anetching step for etching the coating film after the first heating stepto remove the second polymer so that a concavity and convexity structureis formed on the base member; a second heating step for heating theconcavity and convexity structure at a temperature higher than a glasstransition temperature of the first polymer; a step of forming a seedlayer on the concavity and convexity structure after the second heatingstep; a step of or stacking a metal layer on the seed layer by anelectroforming; and a step of peeling off the base member having theconcavity and convexity structure from the metal layer and the seedlayer.
 2. A diffraction grating comprising a concavity and convexitystructure on a surface thereof, wherein the diffraction grating isproduced by a method comprising: pressing the mold obtained by themethod for producing the mold as defined in claim 1 to a transparentsubstrate to which a curable resin has been applied; curing the curableresin; and detaching the mold from the transparent substrate to obtain astructure having a concavity and convexity structure on the transparentsubstrate.
 3. The diffraction grating of claim 2, wherein thediffraction grating is produced by pressing the structure to a substrateto which a sol-gel material has been applied; curing the sol-gelmaterial; and detaching the structure from the substrate to obtain thediffraction grating having a concavity and convexity structure made ofthe sol-gel material.
 4. The diffraction grating according to claim 2,wherein a cross-section shape of the concavity and convexity structurehas a chevron shape; and in a case that a Fourier-transformed image isobtained by performing a two-dimensional fast Fourier-transformprocessing on an concavity and convexity analysis image obtained by ananalyzing a planar shape of the concavity and convexity structure withan atomic force microscope, the Fourier-transformed image shows anannular pattern substantially centered at an origin at which an absolutevalue of wavenumber is 0 μm⁻¹, and the annular pattern is present withina region where the absolute value of wavenumber is within a range of 10μm⁻¹ or less.
 5. The diffraction grating according to claim 3, wherein across-section shape of the concavity and convexity structure has achevron shape; and in a case that a Fourier-transformed image isobtained by performing a two-dimensional fast Fourier-transformprocessing on an concavity and convexity analysis image obtained by ananalyzing a planar shape of the concavity and convexity structure withan atomic force microscope, the Fourier-transformed image shows anannular pattern substantially centered at an origin at which an absolutevalue of wavenumber is 0 μm⁻¹, and the annular pattern is present withina region where the absolute value of wavenumber is within a range of 10μm⁻¹ or less.
 6. The diffraction grating according to claim 2, wherein akurtosis of the cross-section shape of the concavity and convexitystructure is −1.2 or more.
 7. The diffraction grating according to claim6, wherein the kurtosis of the cross-section shape of the concavity andconvexity structure is −1.2 to 1.2.
 8. The diffraction grating accordingto claim 2, wherein an average pitch of a cross-section of the concavityand convexity structure is 10 to 600 nm.
 9. An organic EL elementproduced by stacking a transparent electrode, an organic layer, a metalelectrode in this order on the concavity and convexity structure of thediffraction grating produced by the method for producing the diffractiongrating as defined in claim 2.